Wireless RF controller with CO2 sensor suitable for use with AIROVENT RF MEV WH4H (90001575) Central Extract Units. Enables manual three speed control for every day use, automatic control, where the central extract units built in humidity sensor or the CO2 sensor built into this controller adjusts airflows. There is also an away setting, for low air flows when leaving the property for extended periods. Easy to install to most surfaces. Lightweight with dimensions of  92 x 92 x 23mm. Controller will need a single phase, 230Volt, 50Hz continuous supply.