The Caged Ball LM Guide Actuator Model SKR is a compact actuator that has an inner block, which is a combination of an LM block and ball screw nut, inside a U-shaped outer rail. In addition, by using ball cages in the LM Guide units and the ball screw unit, this model achieves high speeds, low noise, and long-term maintenance-free operation superior to the conventional Model KR. (A ball cage is used only for the LM Guide section of models SKR20 and SKR26 and the ball screw is fitted with a QZ lubricator.)