O\'Neill Psycho One 5/4mm Back Zip Men\'s Wetsuit 2021 - Gunmetal The O\'Neill Psycho One 5/4mm wetsuit has had a re-design this season with the inclusion of Technobutter Firewall inside the suit. This new material is heat retaining thus keeps you warmer for longer in the water. The Firewall is on the chest, back and legs so in all the key areas to maintain body heat. So it nows now far warmer and with the Technobutter 3 neoprene on the arms, shoulders and calfs it is also super flexible. The Psycho One 5/4mm wetsuit is perfect for use in the coldest of winter months in the Uk or if you really feel the cold all year round. Another great thing is it can be used for all water sports and because it features Technobutter 3 neoprene it really feels like you are not wearing a wetsuit at all. This year it also uses Aqua Alpha solvent free lamination and Eco Carbon Black in the neoprene making it a far more Eco friendly wetsuit than ever before. KEY FEATURES - Z.E.N. Zip Closure (Back Zip) - Minimal Seam Design - Anti-Flush Barrier (Z.E.N. Zip) - 360° Barrier With Drainholes (F.U.Z.E.) - Double Seal Collar CONSTRUCTION - Fluid Seam Weld - Arms/ Shoulders/Calf: TechnoButter 3 - Chest / Back/Shins/Butt : TechnoButter 3 Firewall - Aqua Alpha Solvent Free Neoprene Lamination - Eco Carbon Black in Neoprene - Limestone Neoprene - Dope-Dyed Yarn Jersey