Genuine Honeywell 20500 replacement filter for the Honeywell Enviracaire model EV-10, 10500, 17000, 17005. Inside the 20500 box is one hepa filter measuring 11-1/8 OD, 6-1/4 ID, 6" H.. As shown in photo. This True HEPA fiter lasts 1-5 years depending on the concentration of contaminants, operating speed and duration. Genuine Honeywell, as shown in photo.