16ga mild steel capacity. Works on flange up to 2” wide. Forms curve as small as about 1” radius. Forms complete circle with minimum diameter of 2” (shrinker formed circle would be in two pieces if under 6” diameter). Works on any malleable aluminum or steel and many other soft metals, even some vinyl. The bodies are cast iron. The jaws are hardened tool steel to last longer than most careers. Parts including replacement jaws are available if ever (rarely) needed.