Filter dimensions: 21x26x4;Fits the PCO-20C PureAir unit;Uses a MERV 16 pleated filter to capture extremely small airborne particles;This filter only needs to be replaced every 6 months;Genuine Lennox OEM Furnace Filter

• Lennox X6669 MERV 16 Filter - 21 x 26 x 4 - Genuine Lennox Product

Lennox X6669 MERV 16 Filter - 21 x 26 x 4 - Genuine Lennox ProductLennox