Elima-Draft 7 1/4" x 7 1/4" to 8 3/4" x 8 3/4" Insulated Magnetic HVAC Vent Cover For STEEL Vents Save up to 10% annually on your heating bills (Energy Star Home Rated) Keeps existing heat in where it belongs Eliminates cold drafts No tools required Fits STEEL vent size (outside dimensions): 7 1/4 x 7 1/4 up to 8 3/4" x 8 3/4"