This is a stainless steel "Shell in Tube" or "Counter Flow" heat exchanger. The inside tubing is made from 12' of 5/8" convoluted (twisted) stainless steel tubing which continually turbulates the wort as it flows through, and the outer tube is made from 7/8" stainless steel. The chiller allows you to pump wort through without having to restrict your pump to slow down flow. Use 1/2" line to connect to wort in and out feeds. Standard garden hose threaded fittings allow the attachment of a garden hose for the water supply.