The Prolimit Mercury TR free zip steamer wetsuit for men is our best-selling suit. The suit has thermal rebound technology. this is an extra layer in between the neoprene and zodiac that reflects body heat and blocks wind chill. Besides the tr. the neoprene of the suit is 6mm thick. which makes it one of the warmest wetsuits on the market. Compared to the Mercury TR free x. this suit has a zipper at the front that opens up completely for easier access. The seams are taped so they are watertight and protected.