We use a 3/4 HP Airless rated for 4.4 GPM. Wagner Pro Golds. I also have 2 shurflo and Flojet setups for applying sealers but I feel I have more control with the airless. You need to try them and see what works best for you and the products you use (ex: Wolman F & P sprays nicely through an airless... Ready seal is better through a Shur-flo pump setup... in my opinion).