This casement window operator is a left-handed aluminum square body type. It has a 9" steel arm with a round disc on the tip (some older styles had a small wheel instead of a disc). It is worm gear driven by a 3/8" crank spindle. The matching crank handle that fits onto the crank spindle and installation screws are included. Mounting holes available are 3-7/8" and 4-3/4" on center. Part# 1762-ra, aluminum finish