Our premium dental handpiece bearings are engineered to meet the extreme demands of modern dentistry. Designed for high-speed operation, exceptional quietness, and extended service life. Key Specifications: Model: SR144 Dimensions: 3.175x6.35x2.38 mm Balls: Silicon Nitride (Si3N4) Ceramic Races: 440C Stainless Steel (hardened to 58-60 HRC) Tolerance: ABEC-7 (ISO P2 equivalent) Seals: Dual Rubber Shields (RS) or Metal Seals RPM: 400,000 Ceramic balls are standard in our high-end series for their lightweight properties, which reduce centrifugal force, lower heat generation, and enable higher maximum speeds.