This casement operator is constructed of a diecast body, a steel 9 inch arm (with a steel guide button at 9/16 inch in diameter), and a worm gear driven mechanism. It features a square-shaped housing and an operator crank handle, and comes finished in a bronze painted color. This casement operator is left-handed, determined when viewing the window from the outside looking inch It is a surface-mounted design that installs on older, crank-out casement, wood window frames with mounting holes 3-7/16 inch on center. For the opposite handing of this operator, see Prime-Line part 17570-L. Installation fasteners and a set screw (for affixing the crank handle onto the operator spindle) are included with each operator.