These Forgefix Double Cliplock Pipe Clips are made from heat-resistant polypropylene designed to withstand the temperature changes in central heating systems and are effective with temperatures of up to 100°C most pipes in domestic central heating systems operate at around 70°C APPLICATION 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