This hi-limit switch is designed to use with Zodiac Jandy Lite2 LD, LG, LJ pool and spa heater models 125, 175, 250, 325, 400 and also fits Zodiac Jandy LX/LT, LX/LT Low Nox , XL-3 Pool and Spa Heater models 250, 400. 135 Degree fahrenheit temperature.