Linear Bearing LMK12UU 12mm Rod Square Flange Bearing for 3D Printer It is a linear motion system produced at low cost. It is used for infinite stroke and cylindrical shaft. Because the load ball is in point contact with the shaft, the use load is small. The steel ball rotates with very little frictional resistance, so that it can obtain high-accuracy and movement. Linear Bearing LMK12UU 12mm Square Flange Bushing is a low-cost linear motion system used with the cylindrical shaft for unlimited travel. The working load of such bearings is small due to the point contact of the ball and the shaft. The balls can rotate with minimal frictional resistance, thus obtaining high-precision smooth movement. The universal Ball Bearings is great for you to replace the damaged Ball Bearings in your devices to improve the efficiency and save energy. Widely used in home appliances, industrial, low noise and high-speed electric motors, construction machinery, automotive components, pumps, and machinery. Smooth moving, low friction, high rigidity, and long life. Economical, easy to maintain replace. check out : Linear Bearing LMK12LUU 12mm Square Flange Bushing