O'Neill Psycho Tech 4/3 Chest Zip Wetsuit

O'Neill Psycho Tech 4/3 Chest Zip Wetsuit 5 5 4
SKU: ONL4575
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The O'Neill Psycho Tech 4/3 Wetsuit is the new generation of our shop favorite, the Pyrotech. This premium wetsuit has the warmth, flexibility and durability you want in the water and is constructed with high quality materials from one of the greatest innovators in the industry. Made from 100% TB2 Neoprene, the hoodless version of the Psycho Tech is ridiculously stretchy, lightweight, soft and pliable. TB2 truly is a step ahead of the game when it comes to quality neoprene. It is the most advanced super stretch neoprene available on the market. 20% lighter, 30% less water absorption, with improved durability and quick dry properties, you just can't beat it.

O'Neill's F.U.Z.E. system allows for an easy in and out chest zip design while still sealing up nicely to provide a snug fit and prevent flushing in all directions. With the insulating TechnoButter 2-Air Firewall Neoprene in the chest and back panel and the Single Fluid Seam Welds you don't have to worry about getting cold. The Psycho Tech provides all the warmth you'll need so you can comfortably surf anything from 55°F water and up.

O'Neill delivers an amazing coolwater suit that offers lightweight protection from the elements, unrestricted flexibility and superior warmth. What are you waiting for? If you're searching for a superior wetsuit with top end performance and the highest quality materials, look no further than the Psycho Tech.


Thickness: 4/3mm

Neoprene: TB2 and TB2 Air Firewall Neoprene

Seams: Single Fluid Seam Weld

Zipper: Chest Zip

Hood: None

Model Year: 2016

Manufactures Part Number: 4575


Product Features

  • Double Super Seal Neck: A toasty warm two-layer design featuring a 360 smooth skin interior lining, wide adjustability and a secure lock down
  • Single Fluid Seam Weld: Watertight Stitchless Technology that keeps water from entering at all seams and critical points
  • TechnoButter 2 Neoprene: Advanced super stretch neoprene, 20% lighter, 30% less water absorption with improved durability and quick dry properties
  • TechnoButter 2-Air Firewall Neoprene: TechnoButter 2 Neoprene packed with air pockets to reduce water absorption and dry quick
  • F.U.Z.E Entry: Front Upper Zip Entry uses the same zipper technology as the patented Z.E.N. Zip closure keeping you dry without restricting flexibility
  • Red Zone Zipper: Offset zipper with teeth that keeps water from entering
  • Super Seal Cuffs: Fused to create a very low profile at the cuff ending creating the best seal ever. The low profile prevents water entry and improves durability in your wrist and ankles
  • Krypto Knee Padz: Abrasion resistant, high stretch neoprene panel with ergonomic shaping designed to extend the life of the wetsuit and protect the knee while punching through waves
  • External Key Pocket with Loop: Located along the lower leg inseam, this key pocket is easy to access and completely secure
  • Plasma Ankle Seals: Helps prevent flushing through the ankles and keeps a secure fit
  • Strategic Seamless Paddle Zones: An ergonomic, seamless undersleeve panel that allows for unrestricted motion and eliminates rashing
  • LSD (Lumbar Seamless Design): We all know that even the best surfers spend significant amounts of time sitting on their boards. By using a single panel in the rear area of the wetsuit, water entry is minimized and stretch is maximized.


O'Neill Psycho Tech 4/3 Chest Zip Wetsuit Excellent wetsuit Review by tom tom
Best wetsuit I had, it is really worm first day I tried it during the winter or Argentina I spent 3hs surfing, after the 3 hs I was still worm. Really light and flexible. I do really recommend it!

After trying an Xcell wetsuit and the Quiksilver Cypher I can say that this one is way better than the others!!

(Posted on 7/11/2016) 2016-07-11
O'Neill Psycho Tech 4/3 Chest Zip Wetsuit Great SuitReview by Walker Walker
This suit rocks. it's super light, and the enclosure zipper is solid. It doesn't dry as fast as the Flash Bomb, but the light weight makes up for it. Best suit I've owned to date.
(Posted on 4/22/2016) 2016-04-22
O'Neill Psycho Tech 4/3 Chest Zip Wetsuit Oneill is still the bestReview by Scheisshaus Scheisshaus
This is by far the most flexible 4/3 out there, not counting the other Oneill suits. I have recently switched back to Oneill from Xcel and Rip Curl. They are definitely the better suit for larger chested people and the flexibility is a major plus after 30 years of surfing, I'm 41. The chest zip is the largest and easiest to get into of all the suits. Amazingly, it is also the best sealed and very little gets in, even after a head high lip to the shoulder. The fused cuffs may sound gimmicky but they also work extremely well. I used to get leg flushes on hard roundhouses with ALL suits except this one. Good job Oneill. The neck seals well and doesn't choke you because they use thinner rubber in the collar. There is no need for 4 or 5 mil in the neck of a suit. This also allows the use of a light hood to be tucked into the neck and not feel suffocated. TB2 is the best neoprene out there. It dries just as fast as the flashbomb and holds less odor. Plus it's way lighter. All lined suits have a downfall in weight addition. This suit weighs almost half of what my Drylock weighs. Without the linings it actually fits like a second skin. The air firewall works exceptionally well where it is placed. All this praise, but there has to be a catch somewhere, right? Yes, there is. These suits are generally not as warm as a fully lined suit. This is minimal, but noticeable. However the flexibility is so much better that the fix is just a thicker suit. Example: I can wear a 4/3 Drylock all year (Outer Banks), I move to the 5.5/4 hooded Psychotech once the water hits about 48 to 50. This is negated by the fact that these suits are so flexible it's like wearing the next thinner suit. This 4/3 is like wearing a 3/2 Rip Curl. 5.5/4 is like a 4/3. Seriously, it's that stretchy. This suit occupies that 48 to 56 area very well. It could be a all season suit with a polypropylene layer underneath, as long as you don't mind getting a little warm when it's over 60 degrees. I didn't mention seams or construction as it is a nonentity. Oneill has been around since the beginning and there is a reason, quality they stand behind. Just like Cleanline. These guys are always there to help if you need it. If not just order what you need and enjoy the quality service and fast delivery.
(Posted on 3/26/2016) 2016-03-26
O'Neill Psycho Tech 4/3 Chest Zip Wetsuit Damn Good SuitReview by WavePrizm WavePrizm
Pros: This a warm, dry, very flexible suit that fits well (see below). It is light and very flexible so paddling is effortless. The neck seals well and the zipperless design has water flow from top to bottom with no leaks. I had to learn to get in and out of it but after a couple tries it gets pretty easy. The all black style looks great and feels manly. Communications is great with these guys and they helped me order online and got me into the right suit at the best price anywhere.

Cons: This applies to all off the rack suits: I am 5'10", 160 lbs and bought size L. First I ordered a Quicksilver. A wonderful suit overall but was cut for a guy with big thighs and ass but narrow chest and shoulders. I have square shoulders and some chest so all wetsuits are tight across the chest for me. Talked with the rep at Cleanline and decided to return the Quicksilver and go with the O'Neill. Good advice. The suit is more broad up top and shoulders are much more free and flexible but with some pull across the chest. That's the best I can do. It doesn't hinder my paddling so I'm good. I'm not overbuilt but it would take a custom tailored suit to get it just right.

Five stars for this outstanding suit plus excellent, friendly service and great price at Cleanline. Just buy it!
(Posted on 1/2/2016) 2016-01-02

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Size Chart

The staff at Cleanline Surf specialize in sizing O'Neill Wetsuits. If you have never tried an O'Neill suit before, we strongly urge you to call us for expert advice on sizing. We do have a size chart available below, but please take it with a grain of salt. For the perfect fit the first time please call and speak with one of our wetsuit experts.

2XS5′6″-5′8″115-130 lbs32.5-34.5″27-29″
XS5′7″-5′9″125-140 lbs34.5-36.5″28-30″
S5′8″-5′10″135-155 lbs36.5-38.5″29-31″
ST6′0″-6′2″145-165 lbs36.5-38.5″29-31″
M5′9″-5′11″150-170 lbs38.5-40.5″30.5-32.5″
MS5′6.5″-5′8.5″140-160 lbs38.5-40.5″30.5-32.5″
MT6′1″-6′3″160-180 lbs38.5-40.5″30.5-32.5″
L5′10″-6′0″170-190 lbs40.5-42.5″32.5-34.5″
LS5′7.5″-5′9.5″160-180 lbs40.5-42.5″32.5-34.5″
LT6′2″-6′4″180-200 lbs40.5-42.5″32.5-34.5″
XL5′11′-6′1″190-210 lbs42.5-44.5″34.5-36.5″
XLS5′8.5″-5′10.5″180-200 lbs42.5-44.5″34.5-36.5″
XLT6′3″-6′5″200-220 lbs42.5-44.5″34.5-36.5″
2XL6′0″-6′2″210-230 lbs44.5-46.5″36.5-38.5″
3XL6′0″-6′2″230-250 lbs47.5-49.5″38.5-43.5″

Full O’Neill Wetsuit Sizing Chart



If the product is found to be defective under normal use and proper care, O'Neill will repair or replace the product at our sole discretion. The decision to replace or repair a product is made by the O'Neill Warranty Department after receipt of the defective product. At no time does the O'Neill offer refunds. Defective product should be returned clean and dry, postage prepaid. Please include a note with product description, product defects, requested action, return address (be sure to include postal code, especially for Canadian addresses), daytime phone number with area code, customers name and a copy of the purchase receipt sent to the address below.

Suits without a copy of the purchase receipt will NOT BE COVERED UNDER WARRANTY.


  • Products classified as seconds
  • Fading from sunlight
  • Alterations
  • Materials over 1 year (from date of original purchase), or 90 days for accessories
  • Repairs or alterations done by anyone other than O'Neill or an O'Neill authorized repair facility
  • Warranty request without original receipt


Flat-Stitched Products, Glued and Blindstitched Products, and Fluid Seam Weld Products

  • Limited 1-year warranty (from date of original purchase) on workmanship and materials.

Neoprene Dry Suits

  • Limited 1-year warranty (from date of original purchase) on workman ship and materials (waterproof zipper excluded)


  • Limited 90-day (from date of original purchase) warranty on workmanship and materials


For repairs received from the dealer or end user, O'Neill offers:

  • 10 Business Day Turnaround for warranty Stitched Suits
  • 10 Business Day Turnaround for warranty Glued Suits
  • 20 Business Day Turnaround for warranty Fluid Seam Welded Suits
  • 30 Business Day Turnaround for all Non-Warranty Repairs

Repairs are to be returned clean and dry, postage paid. Please include the name and a daytime phone number with area code, return address, product description, and requested action.

Send Repairs To:

O'Neill U.S. Warranty Repair
1022 Bay Marina Drive, Suite 140B
National City, CA 91950
Tel: 1-800-331-1637


Returns are easy! We understand that in some situations returns or exchanges may be necessary. We also want you to be stoked on your purchase. If you are not 100% satisfied with your purchase you may return it for a full refund, or exchange within 30 days of receiving your order. Items must be in new condition with original tags and packaging.

Please make sure your wetsuit fits before taking it in the water. We are not able to take returns or exchanges on used wetsuits.

Click here for our full Return Policy