Steel, nine different sizes to fit Leica M cameras. Used them when I was repairing cameras a long time ago. I thought they were made by HeavyStar but can't find them listed on the bay any longer. Didn't look too long though. When I got them the first thing I did was put a scratch in the advance lever on an M3. Didn't take me too long to figure out they had sharp edges. I use masking tape to raise the wrench slightly off the surface of the camera body & haven't scratched anything since. $70.00 paypal shipped to US.