This free standing inline automatic chlorinator will work for either in-ground or above ground pools. Large capacity 4. 2 lbs. Tank will accept 3 inch chlorine tablets. The chlorinator is fully adjustable so you can regulate the speed at which the tablets dissolve, depending on your pool's chlorine demand. This unit is made of heavy-duty resin. This in-line chlorinator is designed for permanent installation in the pool water return line.