Material: Alloy steel; Inner diameter: 8mm / 0.315 " Overall size: 58 x 34 x 22mm / 2.28" x 1.33 "x 0.866" (L * W * H); Main color: Silver Tone Package: Linear motion ball bearing 1PCS x SC8LUU Linear bearing is widely applied for RepRap 3D printer, food machinery, electronic equipment, machine tensile testing, machine tools multi-axis, etc. The smooth movement and low friction allow energy saving. Designed for solid construction, high rigidity and long service life. Economical, easy to maintain, to replace.