The p131-54m smart-flo+ automatic fuel oil de-aerator represents state-of-the-art technology and is manufactured in accordance with all safety regulations and is tested to factory specifications. provides superior flow characteristics over competitive de-aerator. new, lower profile design for use in tight areas clear chamber allows viewing of oil quality and air content comes with the industry’ highest possible bio-fuel rating: b20 positive shutodd valve for easy-filter change. ul listed 5 year warranty