Metric Labs Jacks feature a rugged construction and a fine screw movement that allows for precision adjustment of vertical positioning of most optical components or equipment, with a maximum weight capacity of up to 55 lbs. Top surfaces are precision finished mounting platforms with ¼-20 and M4 tapped holes (see diagram). The bottom platforms have several additional M6 metric and ¼-20 English sized clearance holes, which are spaced to adapt to common mounting surfaces. Metric Lab Jacks utilize a locking knob to fix vertical position at desired height. Each full revolution of the adjustment knob moves the platform vertically by 1mm.