Pentair 471992 Main Header Assembly Replacement MiniMax Pool and Spa Heater Main header assembly replacement Fits Pentair MiniMax NT STD, NT LN, NT TSI pool and spa heater models 200, 250, 300, 400 Also fits Pentair MiniMax CH pool and spa heater models 150 IID, 150, 200, 250, 300, 350, 400 Measures 12-inch length by 10-inch height by 12-inch width