Product name:LM6UU Linear BearingProduct Features·?Product Name : Linear Ball Bearing;Model : LM6UU·?Material : Carbon Steel, Rubber;Inner Diameter : 6mm / 0.24"·?Outer Diameter : 12mm / 0.47";Length : 19mm / 0.8"·?Color : Silver Tone;Weight : 29gProduct DescriptionThe universal Ball Bearings is great for you to replace the damaged Ball Bearings in your devices to improve them efficiency and save energy.http://www.kuongshun-ks.com/3d-printer/3d-printer-machine-parts/linear-bearing.html