NO KEY NEEDED! SET YOUR OWN CODE - Change the code, not the cover. Because who wants to keep up with another key? This thermostat cover has 3-Digit Combination lock with a changeable code which makes it easy for you to customize. EASY TO INSTALL - Comes with drywall anchors and screws. Simply line up the thermostat guard around your thermostat, plug in the drywall anchors, and the screws and voila! You’re on your way to peace of mind knowing your heating and cooling settings will not be tampered with. FITS OVER EXISTING THERMOSTAT – Nearly universal fit for all thermostats. Guaranteed to fit of any thermostat measuring 7 in wide x 4.5 in height x 2 in diameter. The hinged design makes this thermostat easy to open and access your thermostat when unlocked. SAVE MONEY – Great for use in offices, churches, restaurants, schools and other public areas to control your energy costs. No more sneaky hands changing your heating and cooling! HIGH QUALITY PLASTIC – Made of high quality polycarbonate clear plastic means you’ll be able to see straight crystal clear through the lock box to your thermostat to make sure the settings are exactly the way you want them. The material is also resistant to any stains or yellow tinting that you may see with other cheap plastic covers.