This cam goes on a 5/16" square spindle (shaft) of a lock or handle. It is held on with a set screw. We see these cams used frequently on closet and baggage compartment doors.
Available in two lengths: 1-1/2" and 2-1/4". To determine the one you need, measure from center of your spindle to the end of the cam.
Cams are made of zinc plated steel.
Old Hehr part number 010-198.