The K2 Union suit. IR's K2 fabric is a light weight Malden Mills Polartec® grid fleece (about the same weight as a cotton t-shirt) but it's still remarkably insulating and dries lightening fast. Like the original Union Suit, the neck and shoulders are made with a super stretch neoprene that allow you to climb into the suit via the neck hole- no zippers necessary. The K2 is perfect for shoulder season paddling or summertime on cold water rivers. It can be worn under a drysuit, or even matched with a dry top and paddling pants or shorts. If you've never owned an IR Union Suit before, get ready to fall in love with one piece layering, and if the IR Thick Skin Union suit is already your favorite piece of gear, this is the perfect companion. http://www.immersionresearch.com/store/mens-layering/k2-union-suit/ Video by Effort Inc http://effort.tv