This 21″ whirlpool works perfectly with the 10.5 Gallon Foundry™, brew kettles, and any other brewing system. The rotating rubber piece allows it to secure to the side of any vessel, no matter the thickness. The Swirly™ uses a 1/2″ Straight Pipe Thread for hose connections and includes a hose barb for connecting your water supply. Patent pending. The 21″ Swirly fits any vessel that is 15″-27″ in container height. For smaller vessels, see the 15″ Swirly™.