This rugged lab jack, with a fine screw movement, allows you to precisely adjust the vertical positioning of most optical components or equipment, up to 55 lbs. Top surface is a precision mounting platform with ¼-20 and M4 tapped holes (see diagram). The bottom platform has several additional M6 metric and ¼-20 English sized clearance holes which are spaced to adapt to common mounting surfaces. Locking knob fixes position at desired height. Each full revolution moves the platform 1mm. Dimensions are in mm.