Best To call Before order this part # 1866 840 2870

it fits most Chattanooga Hydrocollator Only

Hydrocollator Over-temp Thermostat for Older M-4 Unit & All Present Model w/ Overtemp Pn# Cw20548

Hydrocollator – OverTemp Thermostat for E1, E2, SS, SS2, M2, M4 Units (120V)