This is a solid brass transom window operator for the window above a door in older buildings. Made from brass rod and heavy brass cast fittings, this is the best operator we have seen. Moving the thumb plate at the bottom of the 11/32" solid brass rod up or down opens and closes the window. The double spring lock retains the window in position. Assembly comes unlacquered. Reversible for use on right or left side of window. Window arm is adjustable for varying thickness of frames.