This Locking Ring prevents the front door on a Voyager thermostat from being opened by unauthorized users. Override, Up/Down buttons are accessible on commercial thermostats while using the locking cover. Various security levels allow you to configure set point limits or render the buttons inoperable with the lock ring installed. Supplied with 2 locking cover keys and designed for easy slip on/off installation. Requires no tools to be installed and the thermostat does not need to be removed or any wiring disconnected to install.