The flow of caulk stops when you stop. As with all dripless guns there is no thumb release, no buttons to push, no special way to click the handle. It's simple and automatic. The model No. CR400 is a professional quality designed gun for daily use and suitable for most caulks and sealants. It features the 29 oz. quart size cradle ratchet drive, ladder hook, and seal punch/cutter. Made of sturdy metal construction and carries a 1 year manufacturer's guarantee.