Heavy duty stainless steel V-Band clamp for turbo discharge setups with industry standard 4" v-band like GT42/GT45 or GT4082. This clamp is made from Stainless Steel. 4" refers to the tube diameter and this clamp is used for industry standard 4" v-band flanges that have an outer edge of about 4.585" to 4.75". 4" refers to the outer diameter of the tube used on this size vband flange.