Heater, Heater System, Gecko, In.Therm, 4.0kW, 60hz in.XM, (#515121) Gecko, Gecko Alliance, Gecko Depot, Alternate OEM#, 0603-409001 As used in Gulf Coast Spas, LX Series, LX 11000, LX11000, LX 9000, LX9000, LX 8000, LX8000, LX 7000, LX7000, LX 5000, LX5000, Pilates H2O, La-Z-Boy, XP1, XP2, XP3,