The squarish clip is for a green cardboard accessory box (old type), solid green color with red writing, at least mine are. A bit into the 50s they changed the size (I think they are white, red and green). There were metal tins too, but I don't think they ever fitted in the clip. The end of the knee lever goes in the smallest metal bit in the top , mine has some sort of additional latch securing the lever in place.
Last edited by Mickey2; 04-23-2019 at 06:12 PM.