Ceiling and Wall Magnetic Vent Covers - Includes 12 Powerful Neodymium Magnets That Ensure a Tight Seal, 3 Pack (5.5 Inch x 12 Inch White) NOW INCLUDES 12 POWERFUL N35 NEODYMIUM MAGNETS  Use as many or as few magnets required for each cover. TIGHT SEAL GUARANTEED  Will manage strong airflows for floor, wall and ceiling registers. COMFORT  Stops drafts and redirects hot or cold air to other rooms. ECONOMICAL - Save money on your energy bill by not heating or cooling unused spaces. SOUND ABSORPTION  Reduce the transmission of sound through your vents. Can be stacked to double or triple noise reduction.