Pentair 472181 Orange Air Pressure Switch Replacement MiniMax Pool and Spa Heater Air pressure switch replacement Fits Pentair MiniMax NT STD, NT STD ASME, Low NOx, Low NOx ASME, TSI, TSI ASME natural gas pool and spa heater models 250, 300, 400 Also fits Pentair MiniMax NT STD, NT STD ASME propane gas pool and spa heater model 250 Available in orange color 0.75 Setting