This Kair Rectangular Airbrick with Damper (Part: DUCVKC651) fits inside Kair Rectangular Flat Ducting 180mm x 90mm. It features a backdraught shutter to prevent unpleasant odours, noises, or draughts flowing back through your duct. The spigot has a depth of 60mm and it is easy to install. It can be used for whole house ventilation, passive stack vent, air conditioning, HVAC, and Heat Recovery Systems. The maximum operating temperature is +60c and the minimum is -15c.