The SuperAir Quick Release Worm Drive Clips s used to close steel. It’s also available for 9 mm and in 9 mm W4 (AISI 304) quality. Locking system for continuous band. You may cut it to any size for fitting different size flflexible ducts. and Band is 9mm width, 0.6mm thickness width rounded edges and smooth underside of banding prevent any risk of damage of the duct of pipe being clamped. Also, Band material is Stainless (SS) steel AISI 430 Galvanized Steel.