The common cable tie, normally made of nylon, has a flexible tape section with teeth that engage with a pawl in the head to form a ratchet so that as the free end of the tape section is pulled the cable tie tightens and does not come undone. When the mouthpiece is inserted through the grooves and pulled tight, it creates a secure, adjustable loop, which locks in place like a knot. Some ties include a tab that can be depressed to release the ratchet so that the tie can be loosened or removed, and possibly reused. Stainless steel versions, some coated with a rugged plastic, cater for exterior applications and hazardous environments