Simple retrofit with included adaptor plate.
Secure Horstmann Wireless Electronic Digital Room Thermostat & Receiver HRT4-ZW
Horstmann Secure E7+ Smart Immersion Heater Control for Economy 7
Horstmann Electronic 7 Water Heater, Multi
Horstmann Electronic 7 Water Heater Multi
Horstmann Electronic 7 Immersion Heater Controller Water Heating Timer Switch
