The water temperature was about 45 degrees and the air temperature was around 40. I was wearing 3mm farmer johns with a light weight top under the the tuilig. I spent about two hours practicing rolls and bracing. The tuilg kept a nice tight seal around the cockpit with almost no water in the boat when I was done. Even though the tuilig is not meant to be a substitute for a "dry suit", I only had a very minimal amount of water get in to my light top around the wrists and neck.
The fact is, my friend and I were very surprised that I was, for the most part, dry when I removed the tuilig after two hours of trying to get as wet as possible. Maybe even more important was the fact I stayed nice and warm the whole time. The light weight "Chillcheater" material delivers, as does their tuilig, it was comfortable and made to fit with plenty of room for movement when laying back in the boat.
It was a great purchase and I will have one in my gear bag from now on.