Large Thermostat Lock Box with Combination Lock, Clear Thermostat Cover Guard on Wall, AC Lock Box Cover Fits Thermostats 4.72"H X 6" W or Smaller (1Pack)Thermostat Cover with LockThe thermostat lock box with key not only prevents others from tampering with and damaging your thermostat, resulting in high bills, but it is also waterproof and dustproof to prevent children from accidentally touching it. For Most ThermostatsThis home type thermostat box is suitable for most thermostats. The outer diameter of the thermostat lock box is 7. 76 inches * 5. 75 inches * 2. 28 inches, the actual usable size is 6.