{"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-bearing-21","title":"Full Ceramic Sealed Ball Bearing Zirconia ZrO2 21.5x31x7mm Full Complement 2RS High-Precision Bearing For Lightweight Durable Smooth Operation In Precision Machinery And Upgraded Applications","description":"\u003cdiv\u003ePremium Ceramic Ball Bearing MR3121-2RS 21.5x31x7 (Single)\u003cbr\u003e\n✔️ Full ceramic ZrO2 seal, 21.5mm ID, 31mm OD, 7mm width \u003cp\u003eThis full ceramic MR3121-2RS bearing uses zirconia (ZrO2) for the balls and races, delivering dry-running performance with excellent wear resistance. Sized at 21.5 x 31 x 7 mm, it’s a solid choice for precision machinery, robotics, CNC tooling, and medical devices where low friction and long life matter.\u003c\/p\u003e \u003cp\u003e✅ Inner diameter: 21.5 mm (0.846 in)\u003cbr\u003e✅ Outer diameter: 31 mm (1.22 in)\u003cbr\u003e✅ Width: 7 mm (0.276 in)\u003cbr\u003e✅ Material: ZrO2 ceramic, full-complement, PTFE seals\u003cbr\u003e\u003c\/p\u003e \u003cp\u003e💡 What is a ceramic sealed ball bearing used for in precision machinery and automation?\u003c\/p\u003e\n\u003cp\u003eThey are handy in automated systems where smooth, accurate motion matters.\u003c\/p\u003e\n- pillow block bearing applications in robotics and automation\n- sealed ceramic bearings for high-speed spindles and clean environments\n- zirconia ceramic bearings offer low friction and corrosion resistance \u003cp\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"VXB","offers":[{"title":"Default Title","offer_id":43545616908523,"sku":"Kit8448","price":49.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0662\/3268\/0683\/files\/mr3121-2rs-full-complement-ceramic-bearing-21-5x31x7-zro2-bearings-vxb-ball-bearings.jpg?v=1770442355"},{"product_id":"smr3121-5-2rs-ceramic-bearing-21-5x31x7-si3n4","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\u003eABEC-5 is a precision rating from the \u003cem\u003eAnnular Bearing Engineers’ Committee (ABEC)\u003c\/em\u003e, indicating that the bearing is manufactured with tighter tolerances for improved accuracy and performance.\u003c\/p\u003e \u003cp\u003eBearings rated ABEC-5 are designed for high-speed, low-friction operation, 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\u003cbr\u003e OldFormat","brand":"VXB","offers":[{"title":"Default Title","offer_id":43546943946987,"sku":"Kit11865","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0662\/3268\/0683\/files\/smr3121-5-2rs-ceramic-bearing-21-5x31x7-si3n4-ptfe-abec-5-bearings-vxb-ball-bearings.jpg?v=1770442404"},{"product_id":"smr3121-5-ceramic-bearing-21-5mm-metric-seale","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\u003eABEC-5 is a precision rating from the \u003cem\u003eAnnular Bearing Engineers’ Committee (ABEC)\u003c\/em\u003e, indicating that the bearing is manufactured with tighter tolerances for improved accuracy and performance.\u003c\/p\u003e \u003cp\u003eBearings rated ABEC-5 are designed for high-speed, low-friction operation, 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\u003cbr\u003e OldFormat","brand":"VXB","offers":[{"title":"Default Title","offer_id":43547195670763,"sku":"Kit13043","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0662\/3268\/0683\/files\/smr3121-5-ceramic-bearing-21-5mm-metric-sealed-abec-5-bearings-vxb-ball-bearings-1.jpg?v=1770442414"},{"product_id":"215317-2rs-sealed-bearing-21-5x31x7-metric","title":"Sealed Chrome Steel Ball Bearing 21.5mm By 31mm By 7mm With Rubber Seals 2RS Self Lubricating High Performance For Machinery Automotive Industrial Use Featuring Chrome Steel Balls And Steel Cage","description":"\u003cdiv\u003eCompact 21.5x31x7 sealed ball bearing, single unit\u003cbr\u003e\n✔️ 21.5mm bore x 31mm outer x 7mm width; chrome steel, double rubber seals \u003cp\u003eThis sealed ball bearing is a compact, high-quality radial unit designed for small machinery, robotics, and hobby CNC setups. It’s built to run smooth at higher speeds and is pre-lubricated with grease for quick, maintenance-light installation.\u003c\/p\u003e \u003cp\u003e✅ Inner diameter 21.5 mm\u003cbr\u003e\n✅ Outer diameter 31 mm\u003cbr\u003e\n✅ Width 7 mm\u003cbr\u003e\n✅ Material chrome steel\u003cbr\u003e\n✅ Cage steel\u003cbr\u003e\n✅ Seals double rubber RS\u003cbr\u003e\n✅ Lubrication pre-lubricated with grease EMQ\u003c\/p\u003e \u003cp\u003e💡 What is a sealed ball bearing used for in small machinery and drive assemblies? This handy part keeps grease in and dust out to extend service life.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eSealed design limits contamination and grease loss in compact systems\u003c\/li\u003e\n\u003cli\u003eHandles radial loads with smooth rotation in tight spaces\u003c\/li\u003e\n\u003cli\u003eIdeal for hobby CNC, robotics, and light industrial drives\u003c\/li\u003e\n\u003c\/ul\u003e \u003c\/div\u003e","brand":"VXB","offers":[{"title":"Default Title","offer_id":43550065328363,"sku":"Kit21084","price":39.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0662\/3268\/0683\/files\/215317-2rs-sealed-bearing-21-5x31x7-metric-vxb-ball-bearings-1.jpg?v=1773354444"},{"product_id":"mr3121-5-full-ceramic-bearing-21-5x31x7","title":"Full Ceramic Bearing 21.5x31x7mm With 21.5mm Inner Bore 6804 Modified Ceramic Ball Bearing For Industrial Machinery Precision Applications And High Speed Systems Such As Robotics CNC Automotive And Aerospace Components","description":"\u003cdiv\u003eFull Ceramic Bearing 21.5x31x7mm single unit\u003cbr\u003e\n✔️ ID 21.5mm, OD 31mm, width 7mm; zirconia ceramic, PTFE cage \u003cp\u003eThese full ceramic bearings are high-performance parts designed for precision machines, robotics, linear slide units, medical equipment, and demanding environments where non-magnetic, corrosion-resistant components matter. The 21.5mm ID bore, 31mm outer diameter, and 7mm width fit standard metric housings used in CNC gear and industrial equipment.\u003c\/p\u003e ✅ Inner diameter 21.5 mm; outer diameter 31 mm; width 7 mm\u003cbr\u003e\n✅ Material: Zirconia ceramic races and balls, PTFE cage\u003cbr\u003e\n✅ Type: Full ceramic bearing, 6804 modified ball bearing\u003cbr\u003e\n✅ Package: 1 bearing per order\u003cbr\u003e \u003cp\u003e💡 What is a full ceramic bearing used for in precision machinery and why choose zirconia?\nA handy, high-performance option for demanding environments:\n- High-speed, low-friction operation\n- Excellent chemical and corrosion resistance\n- Lightweight, non-magnetic construction\n- Long service life in challenging settings\u003c\/p\u003e \u003c\/div\u003e","brand":"VXB","offers":[{"title":"Default Title","offer_id":43555179233515,"sku":"Kit7757","price":49.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0662\/3268\/0683\/files\/mr3121-5-full-ceramic-bearing-21-5x31x7-vxb-ball-bearings.jpg?v=1770442644"}],"url":"https:\/\/vxbtools.com\/collections\/inner-diameter-21-5mm.oembed","provider":"VXB Bearings","version":"1.0","type":"link"}