VERSATILE USE – Use as a floor vent filter for AC vents in warmer months and heating vents in colder months. DIMENSIONS – 4" wide x 10" long x 1/8" thick. EASY TO INSTALL – Simply flip over your register and insert the filter into the bottom of the vent. Works with floor, ceiling, and wall vents in homes or offices. COST-EFFECTIVE – Helps reduce dust and debris accumulation in vents, which may help minimize maintenance needs over time. Northwest Enterprises focuses on providing high-quality air filters at affordable prices. This vent filter media roll can be cut to size and used to cover intake and return registers, air conditioner (AC) vents, or for DIY projects. Works with floor, ceiling, and wall vent registers in homes, RVs, mobile homes, and campers. Directions: Clean the register or vent to be filtered. Measure the vent opening. Transfer the dimensions to the filter using a pen or pencil. Cut the filter to size. Install the filter so air flows through the designated sides.