Elima-Draft Universal Insulated Magnetic Register/Vent Cover for HVAC Aluminum Registers/Vents Fits: 3 Sizes in 1 ELMDFTAIO4370 - The Home Depot

By not covering up your HVAC registers and vents, it
By not covering up your HVAC registers and vents, it's like leaving windows and doors open. Our insulated magnetic covers create a barrier around ceiling and wall registers eliminating heat loss and cold drafts during the winter when your Central Air Conditioner is not in use. If you want to reduce energy costs and feel more comfortable then this product is for you.
Elima-Draft Residential Insulated Magnetic Vent Covers For Aluminum and Steel Vents Come In Multiple Sizes.

ELMDFT-10X10-A - Elima-Draft ELMDFT-10X10-A - 13 x 13 Insulated Magnetic Cover for Aluminum Registers & Vents

Elima-Draft® Insulated Magnetic Vent Cover For Rectangular Vents

Elima Draft Insulated Magnetic Vent Covers

Elima Draft Insulated Magnetic Vent Covers

Elima-Draft 1 in. H X 9 in. W Matte White Aluminum Register Cover - Ace Hardware

Elima-Draft Universal HVAC Insulated Bubble Foil Return Vent Cover ELMDFTRB3433 - The Home Depot

Elima-Draft Air Deflectors at

Elima-Draft® 13x13 Insulated Magnetic HVAC Vent Cover for Aluminum Vents - Staircase Fittings

Elima-Draft Universal Insulated Magnetic Register/Vent Cover for HVAC Aluminum Registers/Vents Fits: 3 Sizes in 1 ELMDFTAIO4370 - The Home Depot