Sundance Spas that use a low flow Smart Heater 6500-301, also use this surface mounted High Limit Disc or Thermal Fuse that shuts off the heater if excessive temperatures are sensed. SPST High Limit switch 314100 replaces the original Sundance 6000-093, and also Len Gordon Surface Mount High Limit 2-05-0110 used on Brett Aqualine, Allied Innovations and Spa Builders Group spa heaters. Also fits Sweetwater Spas that use the 6500-310 Smart Heater. Mounting screws included.