The Salus Optima is a programmable thermostat that interfaces with ZigBee Home Automation Standard networks. The CTL2181-HA can be programmed from the front panel or through the ZigBee network. It supports the Thermostat, Thermostat Interface and Fan Control clusters. It also supports Over-The-Air upgrade and reprogrammability. The CTL2181-HA works with all standard HVAC systems with the ability to support up to 3H2C system.