We manufacture this chiller. We use 25' of 3/8" copper tubing with a high quality brass hose adaptor. It comes complete with a faucet adaptor and all hoses and stainless steel hose clamps. It will cool 5-10 gallons of wort in 15-20 minutes. Indispensable.
Note: this chiller uses a full 25' of copper tubing for more efficient cooling (not 20' like some others). Also, this chillers uses a brass hose adaptor (not plastic) and is meant to last. Finally, a hose adaptor is included so it can easily be adapted for use on your kitchen sink. Other models we have seen do not include this adaptor.