The T4 Honeywell Home thermostat is a programmable, wired 7- day room thermostat. It’s designed to provide automatic temperature and time control of central heating systems in domestic or light commercial premises. Simply wire, power up and test then finally configure Features and Benefits: Compatible with combi-boilers, gas boilers and zone valves. Suitable for use as a temperature sensing device in S or Y Plan systems. Text display and function buttons ensure simplified programming and use. It also displays a continuous time. Optimum start, stop & delay start features that learn how the room is warmed. Twin wire, volt free connections are perfect for use with combi boilers. New improved wall plate with added wiring space. Wired external sensor. Simple button access for the configuration menus. Adjustable Frost protection and energy saving TPI control. Away mode with temperature set (number of days is changeable). Temporary schedule override and the schedule can be turned off. Automatic summer and winter time change. Full 7-day programming with 7 day; 5/2 (preconfigured) or single day schedules. Low battery power indicator. Easy to use battery compartment. Burner 'ON' symbol. Returns Policy - Changed Your Mind? If you change your mind about the product when you receive it you can notify us any time within 365 days and return it for a full refund at your own cost. Any refunds will be made within 30 days of receiving your returned item. You are expected to cover the cost to return the item and your initial delivery charge will not be refunded. More details here