Evaporative cooling vents when not being used in winter can create significant heat loss in winter and increase heating costs. Blocking off these vents can significantly increase energy efficiency and reduce heating costs. These ceiling vent covers install quickly and can be easily removed in summer and reused the following winter.
Fits vents with a face size of up to 400mm x 400mm.

Installation is via a steel hook that grasps the vent. This hook is attached to a cord that is pulled firmly and secured to the central disk. Hence installation and removal is easy and requires no professional assistance.

Also available in 550mm x 550mm - https://www.ebay.com.au/itm/256480372619