American type hose clamp with band thread through-hole, and teeth of the screw fitted in, they have more powerful locking. and accurate Occlusal. Also,american hose clamps can be used in non-circular objects, they can bundle the square columnar objects, such as flue, electric vehicle batteries,etc. Material: W1 Band,housing&screw,all zinc plated. W2 Band and housing with all stainless steel(201ss,304ss,430ss),zinc plated screw. W3 Band and housing with all stainless steel 304,nickel plated screw. W4 Band,housing&screw,all stainless steel 304.