Check the listing for details. 2pack SCS20UU Slide Blocks 20mm Bore for CNC Packaging Equipment 3D Printers. Condition: New. Listed at 30.21 USD. APPLICATION:-Linear ball bearings are commonly used in industrial and commercial applications that require precision linear motion, such as CNC machines, packaging equipment, robotics, and 3D printers.-They offer several advantages over other types of linear bearings, including high load capacity, low friction, and reduced noise and vibration.-Additionally, they are relatively easy to install and maintain, and can be configured to meet specific application requirements.ABOUT THIS PRODUCT:-Linear ball bearings are mechanical devices that allow for smooth linear motion along a track or guide rail.-They consist of an outer sleeve, which serves as a housing, and an inner ball retainer, which contains a series of steel balls that roll between the inner and outer surfaces.