The  O'Neill Psycho One 5/4 mens wetsuit is an incredibly stretchy and warm back-up wetsuit in the O'Neill range. The patented Z.E.N. zip closure (that's the system O'Neill use for the zip on the back) minimises flush. The 5mm wetsuit for men comes with minimal seam design and the seams feature fluid weld making the suit super comfortable and warm. It's made from Technobutter 3 neoprene, O'Neill's top of the range material that we have come to love so much.  Note: The blue in the shoulders is brighter than the picture shows.   Key Features: Patented Z.E.N. Zip Closure Minimal Seam Design Anti-Flush Barier Double Super Seal Neck Construction: Fluid Seam Weld Full Body: Technobutter 3