When used together, these interlocking stems and ferrules provide added coupling integrity to the hose, reduce the chance of bacteria build-up, and provide a clean and consistent end connection. They are particularly designed for rubber hoses that are subject to higher pressures or temperatures during cleaning cycles, however for thick, soft durometer hoses it can result in coupling integrity issues when subjected to excessive heat in long cycles where the hose underneath the metal fitting becomes spongey. These require a crimper to assemble.