{"title":"Inner Diameter - 21.5mm","description":"\u003ch1\u003e21.5mm\u003c\/h1\u003e\u003ch2\u003e21.5mm Online shopping\u003c\/h2\u003e","products":[{"product_id":"mr3121-2rs-full-complement-ceramic","title":"MR3121-2RS Full Complement Full Ceramic Bearing 21.5x31x7 ZrO2 Bearing","description":"\u003ccenter\u003e\n\u003ctable cellspacing=\"2\" cellpadding=\"10\" bg=\"\" border=\"1\"\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"center\"\u003e\u003cfont face=\"Tahoma\" size=\"+2\"\u003eMR3121-2RS Full Complement            Ceramic Sealed Ball Bearing\u003cbr\u003e            Zirconia\u003cbr\u003e            21.5mm x 31mm x 7mm\u003c\/font\u003e\u003c\/td\u003e\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003cbr\u003e\u003cbr\u003e\u003ctable cellspacing=\"2\" cellpadding=\"5\" bg=\"\" border=\"0\"\u003e\u003ctbody\u003e\u003ctr\u003e\n\u003ctd\u003e\u003ctable cellspacing=\"3\" cellpadding=\"5\" bg=\"\" border=\"0\"\u003e\u003ctbody\u003e\n\u003ctr\u003e\u003ctd valign=\"center\" align=\"middle\"\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd valign=\"center\" align=\"middle\"\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" align=\"left\"\u003e\n\u003cp align=\"justify\"\u003e\u003cfont face=\"tahoma\"\u003eMR3121-2RS Full Complement Ceramic              sealed Ball Bearing, measures an inner diameter of 21.5mm,              outer diameter is 31mm and the width is 7mm, Bearing is made from ZrO2 Ceramic Zirconium oxide.\u003c\/font\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eMR3121-2RS Ball                Bearing\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eFull Complement Ceramic                Ball Bearing\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eCage: No Cage\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eBalls: ZRO2 Ceramic\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eClosures: PTFE covers\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eInner\/outer races:ZRO2                Ceramic\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eDimensions: 21.5 mm x 31mm x                7mm\/Metric\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eID (inner diameter)\/Bore:                21.5mm\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eOD (outer diameter): 31mm\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eWidth:                7mm\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eSize:21.5 x 31 x 7 mm\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eQuantity:One Bearing\u003c\/font\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003c\/center\u003e\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\u003ccenter\u003e\u003c\/center\u003e","brand":"VXB","offers":[{"title":"Default Title","offer_id":49309911711937,"sku":"Kit8448","price":49.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0828\/0955\/3089\/files\/mr3121-2rs-full-complement-ceramic-bearing-21-5x31x7-zro2-bearings-vxb-ball-bearings_2b8b1d92-14de-473b-8956-3e8b2c270c95.jpg?v=1748646701"},{"product_id":"smr3121-5-2rs-ceramic-bearing-21-5","title":"SMR3121.5-2RS Ceramic Bearing 21.5x31x7 Si3N4 PTFE ABEC-5 Bearing","description":"\u003ccenter\u003e\n\u003ctable cellspacing=\"2\" cellpadding=\"10\" bg=\"\" border=\"1\"\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"center\"\u003e\u003cfont face=\"Tahoma\" size=\"+2\"\u003e21.5 x 31 x 7 Stainless            Steel Premium ABEC-5 Ball Bearing\u003cbr\u003e            Silicon Nitride Ceramic Balls\u003cbr\u003e            2 PTFE Seals\u003c\/font\u003e\u003c\/td\u003e\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003cbr\u003e\u003cbr\u003e\u003ctable cellspacing=\"2\" cellpadding=\"10\" bg=\"\" border=\"0\"\u003e\u003ctbody\u003e\u003ctr\u003e\n\u003ctd valign=\"center\" align=\"center\" width=\"15%\"\u003e\u003ctable cellspacing=\"3\" cellpadding=\"5\" bg=\"\" border=\"0\"\u003e\u003ctbody\u003e\n\u003ctr\u003e\u003ctd valign=\"center\" align=\"center\"\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd valign=\"center\" align=\"center\"\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\u003c\/td\u003e\n\u003ctd align=\"left\" valign=\"top\" width=\"75%\"\u003e\n\u003cp align=\"justify\"\u003e\u003cfont face=\"tahoma\"\u003e21.5 x 31 x 7 Stainless Steel              Premium ABEC-5 Ball Bearing, Silicon Nitride ceramic              balls, inner diameter is 21.5mm, outer diameter is 31mm              and width is 7mm.\u003c\/font\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003e21.5 x 31 x 7 Ball                Bearing\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eDeep Groove Radial Ball                Bearing\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eClosures: PTFE Sealed\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eQuality: Premium ABEC-5\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eMaterial: Stainless Steel\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eBalls: Silicon Nitride Ceramic                (Si3N4)\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eLubrication: Self Lubricated                (Grease SRL) Bearing\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eDimensions: 21.5mm x 31mm x                7mm\/Metric\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eID (inner diameter)\/Bore:                21.5mm\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eOD (outer diameter): 31mm\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eWidth:                7mm\u003c\/font\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cfont face=\"tahoma\"\u003eQuantity: 1 Bearing\u003c\/font\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003c\/center\u003e\u003c!--Beginning HYBRID CERAMIC BEARINGS--\u003e\u003cp\u003e\u003cbr\u003e\u003csmall\u003e\u003cem\u003eVXB Category: Hybrid ceramic    bearings\u003c\/em\u003e\u003c\/small\u003e\u003cbr\u003e\u003c!--Ending HYBRID CERAMIC BEARINGS--\u003e\u003cbr\u003e\u003c\/p\u003e\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\u003cbr\u003e\u003ch3\u003e💡 What Does ABEC-5 Mean?\u003c\/h3\u003e \u003cp\u003e\u003cstrong\u003eABEC-5\u003c\/strong\u003e is a precision rating from the \u003cem\u003eAnnular Bearing Engineers’ Committee (ABEC)\u003c\/em\u003e, indicating that the bearing is manufactured with \u003cstrong\u003etighter tolerances\u003c\/strong\u003e for improved accuracy and performance.\u003c\/p\u003e \u003cp\u003eBearings rated ABEC-5 are designed for \u003cstrong\u003ehigh-speed, low-friction operation\u003c\/strong\u003e, making them ideal for electric motors, precision tools, 3D printers, and performance equipment where smooth rotation and long service life are essential.\u003c\/p\u003e","brand":"VXB","offers":[{"title":"Default Title","offer_id":49310025646273,"sku":"Kit11865","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0828\/0955\/3089\/files\/smr3121-5-2rs-ceramic-bearing-21-5x31x7-si3n4-ptfe-abec-5-bearings-vxb-ball-bearings_13946f1d-127a-4dd8-b27b-246f77d40746.jpg?v=1748646745"},{"product_id":"smr3121-5-ceramic-bearing-21-5mm-m","title":"SMR3121.5 Ceramic Bearing 21.5mm Metric Sealed ABEC-5 Bearing","description":"\u003ccenter\u003e\n\u003ctable cellspacing=\"2\" cellpadding=\"10\" bg=\"\" border=\"1\"\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"Center\"\u003e\u003cfont face=\"Tahoma\" size=\"+2\"\u003eSMR3121.5 Premium ABEC-5 Stainless Steel Ball Bearing\u003cbr\u003eSilicon Nitride Ceramic Balls\u003cbr\u003e 21.5 x 31 x 7 mm\u003c\/font\u003e\u003c\/td\u003e\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003cbr\u003e\u003cbr\u003e\u003ctable cellspacing=\"2\" cellpadding=\"5\" bg=\"\" border=\"1\"\u003e\u003ctbody\u003e\u003ctr\u003e\n\u003ctd valign=\"center\" align=\"Center\" width=\"\"\u003e\u003ctable cellspacing=\"3\" cellpadding=\"5\" bg=\"\" border=\"0\"\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd valign=\"center\" align=\"Center\"\u003e\u003c\/td\u003e\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\u003c\/td\u003e\n\u003ctd align=\"left\" valign=\"top\" width=\"\"\u003e\u003cfont face=\"tahoma\"\u003e\u003cp align=\"justify\"\u003eSMR3121.5 Premium ABEC-5 Stainless Steel Ball Bearing, bearing is Silicon Nitride ceramic ball.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eSMR3121.5 Ball Bearing\u003c\/li\u003e\n\u003cli\u003eQuality: Premium ABEC-5\u003c\/li\u003e\n\u003cli\u003eClosures: Open\u003c\/li\u003e\n\u003cli\u003eMaterial: Stainless Steel \u003c\/li\u003e\n\u003cli\u003eBalls: Silicon Nitride Ceramic (Si3N4) \u003c\/li\u003e\n\u003cli\u003eDimensions: 21.5mm x 31mm x 7mm\/Metric\u003c\/li\u003e\n\u003cli\u003eID (inner diameter)\/Bore: 21.5mm\u003c\/li\u003e\n\u003cli\u003eOD (outer diameter): 31mm\u003c\/li\u003e\n\u003cli\u003eWidth: 7mm\u003c\/li\u003e\n\u003cli\u003eDimensions: 21.5 x 31 x 7 mm\u003c\/li\u003e\n\u003cli\u003eQuantity: 1 Bearing \u003c\/li\u003e\n\u003c\/ul\u003e\u003c\/font\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003c\/center\u003e\u003c!--Beginning HYBRID CERAMIC BEARINGS--\u003e\u003cbr\u003e\u003csmall\u003e\u003ci\u003eVXB Category: Hybrid ceramic bearings\u003c\/i\u003e\u003c\/small\u003e\u003cbr\u003e\u003c!--Ending HYBRID CERAMIC BEARINGS--\u003e\u003cbr\u003e\u003cbr\u003e\u003cbr\u003e\u003ch3\u003e💡 What Does ABEC-5 Mean?\u003c\/h3\u003e \u003cp\u003e\u003cstrong\u003eABEC-5\u003c\/strong\u003e is a precision rating from the \u003cem\u003eAnnular Bearing Engineers’ Committee (ABEC)\u003c\/em\u003e, indicating that the bearing is manufactured with \u003cstrong\u003etighter tolerances\u003c\/strong\u003e for improved accuracy and performance.\u003c\/p\u003e \u003cp\u003eBearings rated ABEC-5 are designed for \u003cstrong\u003ehigh-speed, low-friction operation\u003c\/strong\u003e, making them ideal for electric motors, precision tools, 3D printers, and performance equipment where smooth rotation and long service life are essential.\u003c\/p\u003e","brand":"VXB","offers":[{"title":"Default Title","offer_id":49310089248961,"sku":"Kit13043","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0828\/0955\/3089\/files\/smr3121-5-ceramic-bearing-21-5mm-metric-sealed-abec-5-bearings-vxb-ball-bearings-1_2f91f7a1-ec6f-4462-ba4e-246807cd03a0.jpg?v=1748646751"},{"product_id":"215317-2rs-sealed-bearing-21-5x31x","title":"215317-2RS Sealed Bearing 21.5x31x7 Metric","description":"\u003ccenter\u003e\n\u003ctable cellspacing=\"2\" cellpadding=\"10\" bg border=\"1\"\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"center\"\u003e\u003cfont face=\"Tahoma\" size=\"+2\"\u003e215317-2RS Sealed Ball Bearing\u003cbr\u003e21.5mm x 31mm x 7mm\u003c\/font\u003e\u003c\/td\u003e\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003cbr\u003e\u003cbr\u003e\u003ctable cellspacing=\"2\" cellpadding=\"5\" width=\"85%\" bg border=\"0\"\u003e\u003ctbody\u003e\u003ctr\u003e\n\u003ctd align=\"center\" valign=\"center\"\u003e\u003ctable cellspacing=\"3\" cellpadding=\"5\" bg border=\"0\"\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd valign=\"center\" align=\"Center\"\u003e\u003c\/td\u003e\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" align=\"left\"\u003e\u003cfont face=\"Tahoma\"\u003e\u003cp align=\"justify\"\u003e215317-2RS Sealed Ball Bearing, bearing is made from Chrome Steel with chrome steel balls and steel cage, 215317-2RS bearing is closed with rubber seals to protect the bearing from dust or any possible contamination, bearing is sealed and self lubricated, the quality is set to EMQ (electric motor quality) to ensure high speed, 215317-2RS bearing is lubricated with grease.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e215317-2RS Ball Bearing\u003c\/li\u003e\n\u003cli\u003eDeep Groove Radial Ball Bearing\u003c\/li\u003e\n\u003cli\u003eCage: Steel\u003c\/li\u003e\n\u003cli\u003eMaterial: Chrome Steel\u003c\/li\u003e\n\u003cli\u003eBalls: Chrome Steel\u003c\/li\u003e\n\u003cli\u003eRadial Clearance: C0\u003c\/li\u003e\n\u003cli\u003eQuality: Electric motor quality\u003c\/li\u003e\n\u003cli\u003eLubrication: Pre-lubricated with grease Bearing\u003c\/li\u003e\n\u003cli\u003eClosures: Double sealed with rubber seals RS\/RS1\/2RS1\u003c\/li\u003e\n\u003cli\u003eSize: 21.5mm x 31mm x 7mm\u003c\/li\u003e\n\u003cli\u003eBearing Inner Diameter: 21.5mm\u003c\/li\u003e\n\u003cli\u003eBearing Outer Diameter: 31mm\u003c\/li\u003e\n\u003cli\u003eBearing Width: 7mm\u003c\/li\u003e\n\u003cli\u003eQuantity: 1 Bearing\u003c\/li\u003e\n\u003c\/ul\u003e\u003c\/font\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003c\/center\u003e\u003cbr\u003e","brand":"VXB","offers":[{"title":"Default Title","offer_id":49310389567681,"sku":"Kit21084","price":34.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0828\/0955\/3089\/files\/215317-2rs-sealed-bearing-21-5x31x7-metric-vxb-ball-bearings-1_abeeb402-35a3-4592-9c8d-c42b3912326f.jpg?v=1748646821"},{"product_id":"mr3121-5-full-ceramic-bearing-21-5","title":"MR3121.5 Full Ceramic Bearing 21.5x31x7mm ID Bore 21.5mm","description":"\u003ccenter\u003e\n\u003ctable cellspacing=\"2\" cellpadding=\"10\" bg=\"\" border=\"1\"\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"Center\"\u003e\u003cfont face=\"Tahoma\" size=\"+2\"\u003e6804 Modified Ball Bearing\u003cbr\u003eFull Ceramic\u003cbr\u003e21.5mm x 31mm x 7mm\u003c\/font\u003e\u003c\/td\u003e\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003cbr\u003e\u003cbr\u003e\u003ctable cellspacing=\"2\" cellpadding=\"5\" width=\"80%\" bg=\"\" border=\"0\"\u003e\u003ctbody\u003e\u003ctr\u003e\n\u003ctd align=\"center\" valign=\"center\"\u003e\u003ctable cellspacing=\"3\" cellpadding=\"5\" bg=\"\" border=\"0\"\u003e\u003ctbody\u003e\n\u003ctr\u003e\u003ctd valign=\"center\" align=\"middle\"\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003ctd valign=\"center\" align=\"middle\"\u003e\u003c\/td\u003e\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" align=\"left\"\u003e\u003cfont face=\"tahoma\"\u003e\u003cp align=\"justify\"\u003e  \t\t\tFull Ceramic Ball Bearing, measures an inner diameter of 21.5mm, outer diameter is 31mm and the width is 7mm, a standard bearing size commonly used in a variety of industrial and commercial applications, Bearing is made from Ceramic.  \t\t\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e6804 Modified Ball bearing\u003c\/li\u003e\n\u003cli\u003eFull Ceramic Ball Bearing\u003c\/li\u003e\n\u003cli\u003eBalls: Made from Zirconia Ceramic (ZrO₂)\u003c\/li\u003e\n\u003cli\u003eCage Material: PTFE (Polytetrafluoroethylene)\u003c\/li\u003e\n\u003cli\u003eRaces Material: Zirconia (ZrO₂) Ceramic \u003c\/li\u003e\n\u003cli\u003eDimensions: 21.5mm x 31mm x 7mm\/Metric\u003c\/li\u003e\n\u003cli\u003eID (inner diameter)\/Bore: 21.5mm\u003c\/li\u003e\n\u003cli\u003eOD (outer diameter): 31mm\u003c\/li\u003e\n\u003cli\u003eWidth: 7mm\u003c\/li\u003e\n\u003cli\u003eSize: 21.5 x 31 x 7 mm\u003c\/li\u003e\n\u003cli\u003eQuantity: One ball bearing\u003c\/li\u003e\n\u003c\/ul\u003e\u003c\/font\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\u003c\/center\u003e\u003c!--Beginning FULL CERAMIC BEARINGS--\u003e\u003cbr\u003e\u003csmall\u003e\u003ci\u003eVXB Category: Full ceramic bearings\u003c\/i\u003e\u003c\/small\u003e\u003cbr\u003e\u003c!--Ending FULL CERAMIC BEARINGS--\u003e\u003cbr\u003e\u003cbr\u003e","brand":"VXB","offers":[{"title":"Default Title","offer_id":49310708236481,"sku":"Kit7757","price":49.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0828\/0955\/3089\/files\/mr3121-5-full-ceramic-bearing-21-5x31x7-vxb-ball-bearings_040b2a52-3728-4773-bb5c-5d2f636147c8.jpg?v=1748646872"}],"url":"https:\/\/smallbearings.com\/ko\/collections\/inner-diameter-21-5mm.oembed","provider":"Small Bearings","version":"1.0","type":"link"}