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O'Neill Men's Psycho 1 Wetsuit 4/3mm Zen Zip FSW Oneill Psycho l Wetsuit - Redesigned

O'Neill Men's Psycho 1 Wetsuit 4/3mm Zen Zip FSW Oneill Psycho l Wetsuit - Redesigned
O'Neill Men's Psycho 1 Wetsuit 4/3mm Zen Zip FSW Oneill Psycho l Wetsuit - Redesigned

O'Neill Men's Psycho 1 Wetsuit 4/3mm Zen Zip FSW Oneill Psycho l Wetsuit - Redesigned

Reg Price $340.00
Item# 4394A05
(8% Savings)
Size: (View Size Tool)


Shipping/Delivery Estimates
Thickness: 4/3mm
Temp: 50°F & up
Activities: Multi Sport
Seams: Single Fluid Seam Weld
Length: Full
Wrist/Ankle: Plasma Seals
Extra: Internal Flood Gate Barrier (Zen Zip) Velcro Resistant Wetsuit
Blue:Technobutter 2 Neoprene
Material Details

Product Description

O'Neill Psycho 1 Wetsuit 4/3mm Zen Zip Fluid Seam Weld - The Psycho 1 men's wetsuit boast new features this season like 100% TechnoButter 2 Neoprene. Now stretchier, 20% lighter, 30% less water absorption and quick drying. 20% Lighter means warmer and less weight on you. 30% less water absorption means you stay warmer. Quick drying, well that means get back in that wetsuit and enjoy doing what you love without that dampness. The new design has a snag free neoprene, velcro will not snag on the neoprene! The Oneill Psycho One ultimate high-performance cold water wetsuit is all new. Enjoy the ultra minimal seam design, less seams means more stretch for you!

The O'Neill Psycho l wetsuit has a single weld along it's already glued and blind stitched seams, this means you have a wetsuit that seams keep the water out so that you can stay warmer. The extra weld means you get to wear your wetsuit longer because it is even more durable than just a GBS (glued and blind stitched wetsuit.) The patented Zen Zip closure system by O'neill keeps you warmer in the core and aids in preventing water from flushing into your wetsuit through the zipper and the neck seals. The Zen Zip closure also has built in drains so that you don't pool water in your wetsuit and feel heavy. The plasma wrist and ankle seals prevent water from flushing up into your wetsuit therefore keeping you warmer. The Plasma also keeps your wrist and ankle seals from blowing out and becoming places where water can flush into the wetsuit. See our video and if you have any questions, don't hesitate to call our wetsuit experts.

Additional Features

  • -ULTRA MINIMAL SEAM DESIGN: Insane flexibility, fit and warmth using a unique design which utilizes less seams
  • -SINGLE FLUID SEAM WELD: Keeps water from entering at all seams and critical points
  • -PATENTED Z.E.N. ZIP ENTRY (WITH DRAIN HOLE): Featuring a pullover internal neck seal that blocks out water for maximum performance. Any water that penetrates the Z.E.N. Collar or Super Short Zip is blocked by the Barrier and forced out the Drain Hole. (U.S. Patent #5,898,934)
  • -TECHNOBUTTER 2 NEOPRENE: The most advanced super stretch neoprene available on the market.
  • -20% lighter, -30% less water absorption with quick dry properties and velcro resistance.
  • -Krypto knee pads
  • -Plasma wrist and ankle seals
  • -External key pocket with loop
  • -Double Super Seal Neck
  • -Strategic Seamless Paddle Zones
  • -Countortionist Seamless Shoulder

Warranty Information

This product has a limited warranty of 12 months.
Learn More

Size Chart   (View Size Recommendation Tool)

Height Weight Chest Waist Hips Neck
5'6-5'8 115-130lbs 32.5 - 34.5" 27-29" 32-34" 14
5'7-5'9 125-140 34.5 - 35.5 28-30 33-35 14.5
5'8-5'10 135-155 36.5 - 38.5 29-31 34-36 15
6'0-6'2 145-165 36.5 - 38.5 29-31 34-36 15
5'6.5 - 5'8.5 140-160 38.5 - 40.5 30.5 - 32.5 35.5 - 37.5 15.5
5'9-5'11 150-170 38.5 - 40.5 30.5 - 32.5 35.5 - 37.5 15.5
6'1-6'3 160-180 38.5 - 40.5 30.5 - 32.5 35.5 - 37.5 15.5
5'7.5 - 5'9.5 160-180 40.5 - 42.5 32.5 - 34.5 37.5 - 39.5 16
5'10-6'0 170-190 40.5 - 42.5 32.5 - 34.5 37.5 - 39.5 16
6'2-6'4 180-200 40.5 - 42.5 32.5 - 34.5 37.5 - 39.5 16
5'8.5 - 5'10.5 180-200 42.5 - 44.5 34.5 - 36.5 39.5 - 41.5 16.5
5'11-6'1 190-210 42.5 - 44.5 34.5 - 36.5 39.5 - 41.5 16.5
6'3.5 - 6'5.5 200-220 42.5 - 44.5 34.5 - 36.5 39.5 - 41.5 16.5
6'0 - 6'2 210-230 44.5 - 46.5 36.5 - 38.5 41.5 - 43.5 17
6'0-6'3 230-250 47-49 41.5 - 43.5 44-46 17.25


How to Select the Right Wetsuit for Your Sport

How to Select a Wetsuit

Intro to Selecting a Wetsuit

When your wetsuit acts as your ‘second skin’, it’s important to do thorough research before investing in this considerable purchase. But how do you choose the right wetsuit? There are a lot of important factors to consider, such as whether you need a wetsuit primarily for swimming, surfing, diving, or multiple sports. While some wetsuits can cross-over into other activities, we recommend investing in a wetsuit that is specific to your main sport. Our guide below is designed to help you overcome any decision-making anxiety, so you can quickly determine your needs and identify your ideal wetsuit.

How do wetsuits work?

A wetsuit is made of neoprene to provide you warmth and protection when doing your favorite water sports. Wetsuits slow down heat loss by trapping a thin layer of water between your body and the wetsuit. While you still get wet, your body heats up the thin layer of water trapped against the body to nearly body temperature. A wetsuit should fit properly. The thicker the neoprene is in the suit, the warmer the wetsuit will be. Research the water temperature in the region where you will primarily use your wetsuit. If temperatures are cold consider wearing neoprene boots, gloves and hoods.

Wetsuit Temperature Guide

Temperature °F

Wetsuit Thickness

Wetsuit Type

Seal Type

80°-74° N/A Rashguard  N/A
73°-66 .5 mm - 1mm Neoprene Top / Shorty N/A
65°-58 2 mm - 3/2 mm Long Sleeve Short Suit Full Suit Flatlock
58°-55° 3/2 mm - 4/3 mm Full Suit + Boots Sealed 
54°-49 4/3 mm - 5/4/3 mm Full Suit + Boots + Gloves + Hood Sealed and Taped 
49°-43° 5/4 mm - 5/4/3 mm Full Suit + Boots + Gloves + Hood Sealed and Taped 
42° and below 6/5 mm // 6/5/4 mm Full Suit + Boots + Gloves + Hood Sealed  and Taped 

Need A Wetsuit For Swimming?

If you plan on swimming a lot or doing laps in your wetsuit, we recommend a Triathlon wetsuit. Triathlon wetsuits are specifically designed for swimmers, with more stretch than a typical surfing or diving wetsuit so you benefit from unrestricted movement while swimming. The extra stretch is due to a different cut, materials, and design than conventional wetsuits.

How Does A Triathlon Wetsuit Work?

Triathlon wetsuits have panels with different thickness and materials (buoyancy) to optimize the swimmer’s positioning. (Note: These wetsuits are not personal flotation devices nor are they intended to protect against sinking or drowning). Additionally, triathlon wetsuits rarely have nylon lament on the exterior so they glide more efficiently in the water with less drag. While these features make a triathlon wetsuit very stretchy, they also make it very sensitive to tearing.

Need A Wetsuit For Surfing?

You may not realize it, but surfing involves a lot of arm paddling. Consider a wetsuit that has stretchier materials in the upper body (shoulders, arms) or in the entire body of the wetsuit. This will reduce the upper body fatigue that results from repetitive motion. (Insert wetsuit diagram here) In this wetsuit example, there are stretch materials in the upper body of the wetsuit to improve your surfing comfort.

Need A Wetsuit For Diving?

The two most important things to consider when determining the best diving wetsuit are: a) Water temperature – If you are diving in colder waters, consider a cold water diving wetsuit. These wetsuits are specifically designed to withstand the compression that results from going deep underwater. They are also typically made of materials that help to maximize your body’s thermal protection. b) Water depth – you may be surprised to learn that the enemy of all wetsuits is depth, not water temperature. As you descend, your neoprene wetsuit compresses very quickly - in some cases to half of its surface thickness within the first 35 feet. So to protect your body and your gear, consider the diving depths you anticipate undertaking before determining the best cold water wetsuit for your needs.

How Does A Cold Water Diving Wetsuit Work?

When you descend down, you experience both water and air pressure. Since water is much denser than air, the pressure increases rapidly as you descend further. With deeper diving come greater wetsuit compression. This compression is actually the bubbles within your neoprene wetsuit -- which act as your insulation -- compressing due to the pressure. So as the wetsuit compresses, it loses thermal protection. While some wetsuits compress more than others in deeper water, the differences are not huge. As you might expect, stiffer, heavier neoprene wetsuits generally compress less than soft stretchy ones.


• At a depth of 34 feet in fresh water, the diver experiences 2 atmospheres of pressure (1 from air pressure, 1 from the 34 feet of water). For every additional 34 feet that the diver descends, he is under an additional atmosphere of pressure. As you can imagine, this is a lot of pressure on a wetsuit!
• At a depth of 90 feet, your 7mm cold-water wetsuit can get very thin depending on the type of neoprene within your diving wetsuit.

Can You Use A Triathlon Wetsuits To Do Multiple Sports?

While a triathlon wetsuit would seem like the perfect wetsuit for multiple sports it, we would strongly recommend against it. For example, if you wore a triathlon wetsuit to go scuba diving, the shoulder straps on your BCD (buoyancy compensator) would likely tear the wetsuit’s neoprene. Other basic actions such as rubbing against coral or the back of a boat as you board, or even kneeling on the ground, would potentially tear a triathlon wetsuit. Due to these high-rip risk factors, we recommend using your triathlon wetsuit for swimming activities only.

When Looking For A Multi-Sport Wetsuit Here Are Some Factors To Consider: 1. What activity will you be spending most of your time doing in the wetsuit? 2. What is your budget? 3. What will be the most active areas of the wetsuit?


Choosing a wetsuit is easy once you determine your primary sporting use: - Do you need a swimming wetsuit? A triathlon wetsuit will give you maximum flexibility with minimal drag. - For surfing, go with a surfing wetsuit that has extra stretch in the upper body – it will greatly improve your comfort. - Are you a diver? A diving wetsuit is your best bet – but the final choice is further impacted by the type of diving that you anticipate doing: cold water or deep dive. - For multiple sport we do not recommend a triathlon wetsuit (even though it seems contradictory)

Any questions?

Our friendly wetsuit experts here at Pleasure Sports (many who would live in a wetsuit if given half a chance!) would be happy to discuss your specific needs and help you find your best wetsuit.