Enhance the air quality in your home with the 12 pack Deflecto HVAC Register Filters. These electrostatic filters are designed to last for 90 days and are perfect for use in register filter 4" x 12" applications. The filters are made of high-quality materials and manufactured in China to ensure their durability and reliability. Each pack contains 12 white pads with dimensions of 12 in (304.8 mm) in length and height, and 4 in (101.6 mm) in width. These filters are compatible with various air filters, indoor air quality and fans, heating, cooling, and air systems. Make sure to change your filters regularly for optimal performance. Can be cut for smaller registers.