Carter Gold Frame filters are made in the USA and washable. Their made with two layers of woven polypropylene, self-charging electrostatic fibers. Sandwiched in between those layers is one extra capacity polyester self-charging filter media for high-capacity dust / contaminant retention. Then these layers are externally supported by an expanded metal mesh support. All of this is then housed in a premium quality extruded aluminum, gold anodized frame with a durable and attractive finish. These filters are designed to last a lifetime and hold a limited lifetime warranty to prove it. The frame is 4 separate pieces with a single screw fastening each corner together. The frame is strong and sturdy ideal for all applications. Gold Frame filters come only in the standard 1? depth. Notes Standard Size Filters will follow industry standard and be 3/8? undercut, i.e. a 12 x 20 will measure 11 5/8? x 19 5/8?. The width of the frames are 7/8?, for 1? filters, respectively. All our air filters have an 1/8? overall tolerance. This means the thickness of the frame could vary up to 1/8?. Cleaning Instructions 1.Simply remove the air filter. 2. Flush with water in opposite direction of air flow arrows then rinse other side. 3. Spray with CEF Cleaner to remove stubborn stains. 4. Rinse thoroughly to remove remaining dirt. 5. Drain excess water, let air dry, and reinstall.