Contrary to most other cold plunges on our list, which use ice or an external chiller, the Sunlight Dwelling Plunge Professional has an integrated chiller that cools water up to 28 degrees Fahrenheit (the bottom on our record). It's a insignificant thing, but we adore the way it simplifies setup, http://brandizze.com/directory/listingdisplay.aspx?lid=22427