The Helix triathlon wetcuit features a reverse zipper, meaning the zipper zips from the top down (the zipper slides down to as you prepare to swim, and you then zip it up to get out of the suit). The advantage to this is that the zipper cannot pull down in the water (i.e., cannot be pulled down inadvertently or otherwise by a fellow competitor). The disadvantage is that it’s harder to put the wetsuit on by yourself. I frankly like the standard zippers better. But I stipulate to the reasoning.