This sash lift is metal with a brass tone finish. The deep inset is ample for three fingers to lift the window. This piece probably dates anywhere from the 1940s to the 1970s. It is new old stock.
The sash lift measures 3 1/4 inches horizontally and 1 3/4 inches vertically. The opening for the inset is 2 1/4 inches by 7/8 inch. The inset is 1/2 inch deep. In order for the piece to lay snugly against the surface of the window, the inset needs to be embedded into the wood. The piece is fastened to the window with brads or screws, the holes located inside the inset. Screws are not provided.