Think Crucial 6 Compatible Replacement Filters W/ Built-In Odor Neutralizing Particle Pre-Filter Designed To Fit all Blueair Brand 500 and 600 Series Air Purifiers HIGH QUALITY AIR FILTER that is designed to replace your Deluxe 500/600 Series Blueair Brand Air Purifier Filter. Get back to breathing clean air again. HEALTHIER LIFESTYLE No one wants to breathe in dirty air and if you don't clean your air filter that will be exactly what you'll be doing. Replacing your filter will help clean your air and allow for a healthier lifestyle. This filter is designed to fit Blueair Brand Model Numbers 501, 503, 550E, 601, 603, 650E and all Blueair Brand 500 and 600 Series Air Purifiers EASY TO INSTALL so you can get back to breathing clean air as soon as possible. Simply remove your old filter and put this brand new one in it's place HIGH QUALITY AIR FILTER that is designed to replace your Deluxe 500/600 Series Blueair Brand Air Purifier Filter. Get back to breathing clean air again. HEALTHIER LIFESTYLE No one wants to breathe in dirty air and if you don't clean your air filter that will be exactly what you'll be doing. Replacing your filter will help clean your air and allow for a healthier lifestyle. This filter is designed to fit Blueair Brand Model Numbers 501, 503, 550E, 601, 603, 650E and all Blueair Brand 500 and 600 Series Air Purifiers. EASY TO INSTALL so you can get back to breathing clean air as soon as possible. Simply remove your old filter and put this brand new one in it's place