AST Works 2 Pcs LMF6UU 6mm Inner Diameter Round Flange Linear Bearing Bushing CNC Router Low coefficient of frictionreliable friction characteristics that do not increase over the life of the bearingbuilt in double seals standardadvanced polymer resin cage for quieter operationthe universal ball bearings is great for you to replace the damaged ball bearings in your devices to improve them efficiency and save energy. Widely used in home appliances, industrial, low noise and high speed electric motors, construction machinery, ponents, pumps, and machinery. Smooth moving, low friction, high rigidity and long life. Economical, easy to maintain and replace