This notched steel lever was used as the window prop on early 1950s Boles Aero, Spartan and several other makes. It comes in either a right hand or left hand version. We're making these from 12 gauge 304 stainless steel, which is far superior to the original mild steel version.
The right hand version is shown in the photo. The left hand version is identical but with the handle bent the opposite direction.
The overall length is 5" and it has a 5/32" hole in the end of the lever where it attaches to the window sash.