Santon - Immersion Heater Water Thermostat EY311C 14" Immersion 2 1/4" Boss size Compatible with: Santon R Units (R24, R45, R70, R115) Water Heaters PLEASE NOTE REMOVAL OF THE THERMOSTAT CAP IS STRICTLY FORBIDDEN. TAMPERING WITH THE CAP OR RETURNING TO US WITHOUT THE SCREWS WILL INVALIDATE YOUR WARRANTY.