Water Temp Rating * 45-50 Degrees & Up
Style Fullsuit
Thickness 4/3mm
Neoprene Type 100% Stretch
Seam Construction Sealed & Liquid Taped
Zipper Style Short Back Zipper
Internal Features Poly Fleece Lining
Additional Features Key Pocket & Kneepads
Warranty 1yr
Manufacturer's Part Number 4405
* Water temperature ratings are only a guide and are very subjective. If you are cold, get out of the water and seek warmth.
Allergy notice: It's rare, but neoprene (wetsuits) and/or the materials used in its construction can cause allergic skin reactions. If allergic, discontinue use and consult a physician.
Warning: California Proposition 65
Warning: This product can expose you to chemicals including Chloroprene, which is known to the state of California to cause cancer and birth defects or reproductive harm. For more information, go to

O'Neill Size Chart:

O'Neill Wetsuits Size Chart

Wetsuit Reviews: 4/3mm Men's O'Neill HEAT Full Wetsuit

Average Customer Review: 5 out of 55 out of 55 out of 55 out of 55 out of 5 - 19 Reviews

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5 out of 55 out of 55 out of 55 out of 55 out of 5 Perfect fit. Excited!
Reviewer: Robert   |  12-19-2017

Great fit to sizing chart. I am a large. Excited to use it.

4 out of 54 out of 54 out of 54 out of 54 out of 5 long time user
Reviewer: Richard Page   |  5-11-2017

Best wetsuit model for the money. Weakness is in the zipper.

5 out of 55 out of 55 out of 55 out of 55 out of 5 Odd size fits great!
Reviewer: Patrick   |  6-2-2016

I'm 5'8" and 225 lbs. so I ordered the 2XLS. It fit perfectly.

5 out of 55 out of 55 out of 55 out of 55 out of 5 Fantastic Investment
Reviewer: Dennis Mathews   |  5-25-2016

Simply perfect!

5 out of 55 out of 55 out of 55 out of 55 out of 5 Comfortable
Reviewer: Tom   |  3-14-2014

First, 2XLS Heat fits my 5'5", 215 lbs frame: its easy to get on and off. Most importantly it is very warm and much less restricting that the vintage 4/3 Evolution it replaces. Can't speak to durability, but after two windsurfing sessions, 62 degrees air, and 55 degrees water, temperatures, I am very satisfied.

5 out of 55 out of 55 out of 55 out of 55 out of 5 gotta upgrade
Reviewer: greg   |  1-11-2014

Felt a little tight in the shoulders and back first time out , but it loosened up the more I went surfing. I'm about 185lb and 6ft so I bought a large and love it. Thought I would use it throughout the winter too however 38-40 degree water and winter winds have changed my perspective. Great for fall but gotta get a 5/4/3 or a 6/5/4 if i'm going to stay warm, thats me though. Not much meat on my bones and in retelatively trim in shape.

5 out of 55 out of 55 out of 55 out of 55 out of 5 Excelent suit!
Reviewer: Phil   |  8-24-2013

This Suit is very well constructed many years of use to be had. Neoprene is warm comfortable light weight with no movement restriction which will make for great rides I'm stoked for winter.

3 out of 53 out of 53 out of 53 out of 53 out of 5 Good impression but product quality issue caused a return
Reviewer: Tommy in Texas   |  2-25-2013

I evaluated three different 4/3 suits: Oneil Psycho 3, Oneil Heat, and Xcel Infinity Drylock. Each was used for a slalom waterski session with the lake temp and air temp around 60 degrees. You can see my detailed reviews for each suit under their respective product sections. The Heat gave a good overall impression and is a fine mid-range suit. It was very easy to put on and take off without any assistance from another person. The back zip flap is pretty small and allowed some amount of water that leaked thru the zipper to reach my skin which I didn't care for. The neoprene is very flexible and feels like a second set of skin and doesn't overly compress my body. It's almost like I'm not wearing any suit which makes it very comfortable. The seams are sewn inside and sealed on the outside and unfortunately the seal on my right leg failed after a short amount of time skiing with a 1/2" gap being created which allowed water into my leg area. I'm very happy with the excellent support provided by Dave M at Wetsuit Wearhouse who allowed me to return the suit due to this defect. He says these suits rarely fail like that so perhaps my issue was a one-off situation.

4 out of 54 out of 54 out of 54 out of 54 out of 5 Great suit if you can get into it
Reviewer: Bob   |  1-16-2013

As noted in other reviews, the suit is of excellent quality, par for O'Neill. I am between sizes; a large is too small, and a XLS is too long, so I can't say I got a great fit. Because of reduced flexibility in the shoulders, getting into the Large was virtually impossible. Also, the zipper is exceptionally sticky, and unless you can reach around and hold the back of the suit down as you pull up on the cord to zip, you will need a buddy to help. If getting in and out of a suit is an issue for you, I had much better luck with O'Neill's low-end suit; the Epic II. It has a slightly longer zipper, which made entry easier. Don't expect this suit to be as warm or last as long as the HEAT, but it will do. For ultra-cold conditions, add an O'Neill hooded vest.

5 out of 55 out of 55 out of 55 out of 55 out of 5 Emperor of wetsuits
Reviewer: Bill McClain   |  12-19-2012

I'm a big guy. Most companies don't even carry a 3X. This suit fits me good. Keeps me nice and toasty. It does everything O'Neill said it would do. Life is getting too short (62) for me to put my boards up for the Winter.

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