This is non-handed casement operator for butt-hinged casement windows. It has a 10-3/4 in. rotating arm and is only 1-3/8 in. between screen and sash. It is driven by a heavy cast worm gear and has a full 90 degree motion in both directions. Found on Parlyn Windows as well as a variety of other window manufacturers. For brass version use Prime-Line part H 3687. Brass crank handle is included.