Engineered to Tough PPP standards these units feature the same high quality design as our standard water hammer arresters, with the exception of the seal rings and the addition of the high pressure filler cap at the top of the arrester. The arresters shown are rated for 2,000 psig maximum spike operation. Finished to your specifications The expected spike pressure must be specified as well as the chemical make-up of the fluid in the system and the maximum temperature when ordering. arresters may be charged at the factory with either air or dry nitrogen per your specification. If arresters are to be used in systems pumping volatile fluids, it is mandatory that they are charged with dry nitrogen.