Product pack: 10 pieces of SMR125C 2OS hybrid ceramic bearings, size 5 x 12 x 4 mm. Also referenced models and sizes: SM125 2RS ceramic bearing 5 x 12 x 4 mm, MR125RS reel bearing, and SMR128C2OS 8 x 12 x 3.5 mm for compatibility checks. Key benefits Smoother rotation and lower friction: hybrid ceramic rolling elements reduce contact friction compared to allsteel designs, improving rotational smoothness in small speed assemblies. Improved heat and wear performance: ceramic elements resist wear and run cooler under load, extending service life in demanding hobby and precision applications. Sealing and protection: 2OS and 2RS sealing options help keep contaminants out and lubricant in, reducing maintenance frequency. Precise fit and consistent sizing: standard dimensions 5 x 12 x 4 mm make these bearings a direct replacement for common SM125 and MR125 series parts when the same dimensions are required. Product attributes Model: SMR125C 2OS Quantity: 10 pieces per pack Size: 5 x 12 x 4 mm Variant references: SM125 2RS 5 x 12 x 4 mm, MR125RS, SMR128C2OS 8 x 12 x 3.5 mm Construction: hybrid ceramic rolling elements with metal races for balance of durability and precision Seal type: 2OS or 2RS style for doubleside protection How this solves common problems Reduces vibration and noise in small motors and reels by delivering more consistent rolling performance. Limits frequent bearing replacement in hobby gear and precision assemblies by offering better wear characteristics than standard steelonly bearings. Simplifies repairs and upgrades: standard sizing and familiar model numbers make selection and retrofit straightforward. Typical applications Hobby electric RC: motors, gearboxes, and servos where compact, speed bearings are required. Fishing reels: precision reel bearings that need low friction and good sealing to resist ingress of debris. Small electric motors and precision spindles: tasks requiring consistent rotation and reduced heat buildup. Installation and selection tips Verify outer and inner diameters and width before installation to ensure correct fit for SM125 or MR125 series housings. Clean the housing and shaft prior to pressing bearings in to prevent misalignment or premature wear. Use compatible lubricants if relubrication is needed; sealed bearings may not require immediate relubrication. If you need a reliable replacement or upgrade for small speed bearings in hobby and precision equipment, this 10 piece pack of SMR125C 2OS hybrid ceramic bearings offers standard sizing, improved running characteristics, and sealed protection for longer service life.