Vevor Air Scrubber 3 Stage 550 CFM or 4 Stage 800 CFM MERV10 Carbon H13 HEPA NewThe 3 stage and 4 stage filtration systems effectively clear all pollutants from your home. The high airflow of 550 CFM or 800 CFM makes it more suitable for heavy duty restoration work. A perfectly adapted filter size prevents impurities from escaping. Our control panel has clear functional guidelines. You can daisy chain up to 3 units of the 550 CFM model to achieve a combined airflow speed of 1650 CFM, and daisy chain up to 3 units of the 800 CFM