ForgeFix Pipe Clip Single Openlock - ForgeFix PCSO22, These Forgefix Single Openlock Pipe Clips are made from heat resistant polypropylene, designed to withstand the temperature changes in central heating systems. They are effective with temperatures of up to 100°C (most pipes in domestic central heating systems operate at around 70°C). Used when fitting most types of pipe work. Polypropylene, also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. An addition polymer made from the monomer propylene, it is rugged and unusually resistant to many chemical solvents, bases and acids. ForgeFix PCSO22 Pipe Clip Single Openlock 22mm Box 100