This Boston Gear NR2025 anti-friction bearing is a ball bearing sheave or pulley for rope, wire rope, and applications requiring a semi-circular tread. It has hardened raceways for resistance to wear and a pressed steel sheave for strength and durability. The bearings are unground, for applications with moderate loads and speeds. This ball bearing sheave has a .5" bore for attaching to a shaft and a radial load capacity of 334 lb at 100 revolutions per minute (rpm).

Rolling bearings use rolling elements to maintain the separation between moving parts to reduce rotational friction and support radial and axial loads. These elements can be one of the following types: ball, cylindrical, spherical, barrel, needle, spindle, or tapered. All rolling bearings are open, shielded, or sealed. Sealed bearings are lubricated with oil or grease in the bearing factory, while open and shielded bearings are meant to be lubricated in place, with periodic reapplication of lubrication, based on use. The shield protects the working parts of the bearing from environmental debris that may be introduced and could reduce the ball bearing speed and lifespan. Rolling bearings are used in a range of applications from agricultural machinery to conveying equipment, robotics, dental equipment, elevators, rolling mills, ship rudder shafts, and aggregate crushers, among others.

Boston Gear manufactures gears, gear drives, bearings, valves, shaft collars, couplings, and other power and fluid transmission components. The company, founded in 1877, is headquartered in Charlotte, NC, and meets International Organization for Standardization (ISO) standard 9001:2008 standard.