The BZ 400 thinsulate undergarment has changed the face of diving thermal protection. It was the first thinsulate undergarment to stabilise the thinsulate material to prevent the material from degrading and gathering in the ankles. Since then the features have been improved to include mobility panels around the shoulders, heating and p-valve ports, non-wicking wrist cuffs to minimise the effects of minor seal leaks, and a warm collar coming high up the neck, but keeping clear of the seals.
This undersuit is an excellent basis for cold water diving. It is a phenomenal suit and will keep you warm, comfortable and flexible throughout your dive.