Pet Dander Reducing Air Vent Filters 4x12 (Register Vent Filters) 1 Pack of 12Qty Per Unit: Package of 12 Register Pet Dander Reducing Air Vent Filters MERV 8 Electrostatic Register Vent Filtration Pet Dander Reducing Air Vent Filters have a permanent electrostatic charge to help trap dirt, dust, pet dander, dust mites, and pollen sized particles through furnace AC registers. Keeps dirt and objects from falling into ducts. Can be trimmed to fit standard size vents 4 X 12 and under. Air Register Vent Filters are made of a self