Cast iron. Shown in the 1915 Penn catalog with Lebraun design page 264 and with Riva design page 298. The knob is a variation ofI-10100. The center has one large bump. The face of the knob is wrapped by the rear where as in I-10100 the face wraps around the rear part. Two examples of the Penn knob are shown. In example A the rear and stem are one piece. In example B the stem seems to be screwed into the rear. The window lift is an example of the Lebraun design.