O'Neill Psycho One 5/4mm Full BZ Men's Wetsuit - (Gunmetal/Ultrablue) - 5427

Size: S
Sale price£279.95
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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.


- 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


- 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


Technobutter 3 Neoprene

O’Neill’s exclusive new pre-stretched neoprene with featherlight, ENVY foam rubber core. Ultimate, flexibility, warmth and comfort. Built to last.

Single Fluid Seam Weld

O’neill’s exterior fluid seam weld is a revolutionary seam construction that utilises a non-chafing high-grade, silicone-based urethane applied in liquid form to outside of a glued and blindstitched seam completely blocking out water without restricting flexibility.


Patented Z.E.N. Zip Entry with Drainhole

O’Neill’s innovative patented Z.E.N. Zip Entry system is the most imitated entry/closure system in the world. This free floating exterior mini zip allows for a zipperless feel and stops water from entering the wetsuit. (U.S. Patent #5,898,934). Pullover internal seal that blocks out water for maximum performance. Water that penetrates the Z.E.N. Collar or Super short zip is blocked by the Barrier-2 and forced out the drain hole.

Double Superseal Neck

A toasty warm two layer design featuring a 360˚ smooth skin interior lining, wide adjustability, and a secure lock down. Fully adjustable and watertight.


Strategic Seamless Paddle Zones

2020 O’Neill Psycho One 5/4 Back Zip has an ergonomic, seamless under sleeve panel that allows for unrestricted motion and eliminates rashing. Flexible and unique design which utilizes minimal seam placement for comfort.

Sidewinder S-Curve Seams

Sidewinder S-Curve seams.


Krypto Knee Pads

Abrasion resistant, high stretch neoprene panel with ergonomic shaping for comfortable durability. Flexible and unique design utilises and extended knee pad for added durability.


External Key Pocket with Loop

Abrasion resistant, high stretch neoprene panel with ergonomic shaping for comfortable durability. Located along the lower leg inseam. Constructed with Fluid Seam Weld and UltraFlex DS neoprene, this key pocket has added strength, easy access and completely secure.

The 2021 O’Neill Psycho One 5/4 Back Zip – perfect for those colder winter months.

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