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O'Neill Heat 4/3 Wetsuit

O'Neill Heat 4/3 Wetsuit 5 5 7
SKU: ONL4405
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Availability: In stock


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No Hassle 30 Day Return Policy. Doesn't fit? Don't like it? Return it.

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Family Owned Since 1980. Online since 1999.


Cleanline Staff Member Matt Cleanline Staff

Matt Says:

"The O'Neill Heat 4/3 Wetsuit has been updated with a classic look, but this is still the Heat that we know and love. A great mid range wetsuit featuring an exterior fluid seam weld for durability, smooth skin chest and back for added warmth, and a back zip entry for easy on and off. Now that the neoprene has been updated to 100% UlraFlex DS (super light and stretchy) it is a better value than ever. One of the best selling O'Neill wetsuits out there, which is why you can get it in some of the hard to find sizes like XXLS and XXXXL. Great suit!"


The O'Neill Heat 4/3 Wetsuit continues to wow with the number of high end features you get for such an amazing price. Not only is the Heat Wetsuit made from ultra gooey UltraFlex DS Neoprene and warm FluidFlex Firewall, but it's also sealed with Single Fluid Seam Welds. Add in a redesigned zipper panel with a Red Zone Zipper, easy-in-easy-out usability, clean retro graphics and this suit is hard to beat.


  • Thickness: 4/3mm
  • Neoprene: UltraFlex DS Neoprene
  • Seams: Single Fluid Seam Welds
  • Zipper: Back Zip
  • Hood: None
  • Model Year: 2017/2018
  • Manufacturers Part Number: 4405

Product Features

  • UltraFlex DS Neoprene/Smooth Skin UltraFlex Firewall
  • Exterior Single Fluid Seam Welds
  • Double Super Seal Neck
  • Red Zone Zipper
  • External Key Pocket with Loop
  • Sidewinder S-Curve Seams
  • Krypto Knee Padz
  • LSD (Lumbar Seamless Design)
  • Strategic Seamless Paddle Zones


O'Neill Heat 4/3 Wetsuit old suit blew outReview by rubba dubba rubba dubba
so far so good, fits eccel. , easy to get on and off, O'neil could make the zipper tag line 2 inches longer but no big deal. Cleanline is a pleasure to do business with, recommended them to a friend when he couldn't find the right size. Thanks!
(Posted on 8/6/2018) 2018-08-06
I recently purchased an SUP board and decided to get a 4/3 Heat so I could try out the board before everything here in Wisconsin turns to ice. I own some other lower-quality wetsuits and have to say I was absolutely amazed at how warm this suit is while not being restrictive at all. The water I was on had some ice floating in it, and the air was about 35 degrees. I fell in once at the beginning of my session and continued on for over an hour and never felt cold.

The back zipper initially let in a tiny amount of water, but let's face it...it's called a WETsuit for a reason! The welded seams are awesome because they're sealed up like Fort Knox. The neoprene itself is super stretchy and, with the help of the friendly Cleanline staff, I found that the XLS size fits me like a glove.

The staff at Cleanline were awesome to work with and the suit came with a personalized hand-written note and a few Starburst candies. A dude who wears an XLS really doesn't need candy, but hey, it was a nice touch!
(Posted on 11/14/2017) 2017-11-14
O'Neill Heat 4/3 Wetsuit The best wetsuit I've ever hadReview by Neco Neco
I've been wearing o'neill wetsuits for over twenty eight years and this model is by far the best of all. Ultraflexible, warm, easy to put on and take off , and the classic design is awesome. I recomend it one hundred percent.
(Posted on 6/13/2017) 2017-06-13
O'Neill Heat 4/3 Wetsuit Comfy warm suitReview by DoubleD DoubleD
What a difference a new suit can make! This suit is comfortable and warm. I'm glad I got the back zip because I am over 50 and it is really easy to get in and out. Cleanline sent a bunch of goodies and handwritten note in my box when everything arrived, which was a nice personalized touch.
(Posted on 1/30/2017) 2017-01-30
O'Neill Heat 4/3 Wetsuit WARM AND COMFORTABLE Review by Brostertado Brostertado
This is my first 4/3 wetsuit and I'm extremely satisfied. I used it the day after Christmas in 58 degree water and stayed nice and warm. I used the size chart hoping to get the right size and mine fits perfect. Worth mentioning, Cleanline surf was excellent to work with. Fast delivery and good service.
(Posted on 12/27/2016) 2016-12-27
O'Neill Heat 4/3 Wetsuit best wetsuit i have own Review by murph murph
the 4/3 O neil heat way better quality then my previous 4/3 O neil epic. The 4/3 heat easy on and off love the welded seams and keeps the heat in
(Posted on 12/21/2016) 2016-12-21
O'Neill Heat 4/3 Wetsuit Quality suit, great price, amazing service with CleanlineReview by hilaria hilaria
Perfect suit for the SoCal winters. Firewall interior keeps you toasty in the lineup. Doesn't feel like a 4-3, surfs more like a 3-2 due to the strechy factor of the material.
(Posted on 1/5/2016) 2016-01-05

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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.

XS5′7″-5′9″125-140 lbs36.5-37.5″28.5-29.5″
S5′8″-5′10″135-155 lbs37.5-39″29.5-31″
ST6′0″-6′2″145-165 lbs37.5-39″29.5-31″
M5′9″-5′11″155-170 lbs39-41″31-33″
MS5′6.5″-5′8.5″145-165 lbs39-41″31-33″
MT6′1″-6′3″160-180 lbs39-41″31-33″
L5′10″-6′0″170-190 lbs41-43.5″33-35″
LS5′7.5″-5′9.5″160-180 lbs41-43.5″33-35″
LT6′2″-6′4″180-200 lbs41-43.5″33-35″
XL5′11′-6′1″190-210 lbs43.5-46″35-37″
XLS5′8.5″-5′10.5″180-200 lbs43.5-46″35-37″
XLT6′3″-6′5″200-220 lbs43.5-46″35-37″
2XL6′0″-6′2″210-230 lbs46-48.5″37-39″
2XLS5′9.5″-5′11.5″200-220 lbs46-48.5″37-39″
3XL6′0″-6′3″230-250 lbs48.5-51″39-44″
4XL6′1″-6′4″250-270 lbs51-53.5″44-48″

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

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