Deep groove geometry for high speeds and supporting both and axial loadsChrome steel for durability and resistance to deformity under heavy loadsMetal shields on both sides of the to keep lubricant in and contaminants outLubricated at manufacturer for no additional lubrication requiredThis 604ZZ 4x12x4-millimeter shielded miniature ball has deep groove geometry for high speeds and supporting both and axial loads. chrome steel construction makes it durable and resistant to deformity under heavy loads. Material: SteelColor: SilverThe metal shields on both sides of the keep lubricant in and contaminants out, and it comes -lubricated from the manufacturer so that no additional lubrication is required. This deep-groove shielded miniature ball is for use in applications that involve combined and axial loads and a need for high running accuracy at high rotational speeds. Such applications include clutches, drives, gearboxes, compressors, pumps, turbines, and printing and textile machines, among others.Rolling bearings use rolling to maintain the separation between moving parts to reduce rotational friction and support and axial loads. Sealed bearings are lubricated with oil or grease in the , while open and shielded bearings are meant to be lubricated in place, with periodic reapplication of lubrication, based on use. The protects the working parts of the from environmental debris that may be introduced and could reduce the ball speed and lifespan. Rolling bearings are used in a range of applications from agricultural machinery to conveying equipment, robotics, dental equipment, elevators, rolling mills, rudder shafts, and aggregate crushers, among others.Package Contents: 10 x Deep groove Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.