The ACC0620 Locking Ring prevents the front door on a Slimline 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. Requires no tools to be installed and the thermostat does not need to be removed or any wiring disconnected to install.