Sold in pack of 8 High Quality RJ4JP-01-08 Sold polymer Linear bearing a direct replacement for the metal LM8UU bearing commonly used in many 3D Printers. Ideal for RepRap, Prusa, Mendel, etc. Igus RJ4JP-01-08 for use with 8mm rod. Made in Germany Igus RJ4JP-01-08: Lubricant-free alternative to ball bearings with Japan dimensions Long-life Quickly installed, secured by circlips Light and clean Typical applications:3D printers, gantries