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O'NEILL

O'Neill Men's Thermo X Short Sleeve Insulative Top

  • Based on 226 reviews
Condition: New
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Availability: In Stock.
Fulfilled by Amazon
Arrives Sunday, Oct 18
Order within 2 hours and 44 minutes
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Size: Large


Color: Black


Features

  • Other Fibers
  • Imported
  • Skin Cancer Foundation Recommended Product; UPF 50+ Ultraviolet Protection
  • Perfect For Chilly Days When An Extra Layer Of Warmth Under Your Wetsuit Is Needed
  • Thermo-X Layering Fabric Provides Incredible Insulation With Low Bulk And Quik-Dry Properties
  • 220g Nylon/Spandex Includes Water Repellency And Odor Resistance
  • ***Super Low Neck: No Interference With The Neck Of Your Wetsuit

Description

The O’Neill Men’s Thermo-X Short Sleeve Crew delivers quick-dry, lightweight insulation, UV protection, and comfort in and out of the water. Designed with a performance fit, it moves like a second skin for maximum mobility and layering versatility. The U.P.F. 50+ rating shields against harmful rays, while the quick-dry 4-way stretch fabric and flatlock seams add durability and comfort. Featuring Thermo-X HyperDry technology, this top minimizes water absorption while providing insulation and rash protection. Ideal for surfing, swimming, paddling, kayaking, wakeboarding, waterskiing, snorkeling, diving, windsports, or simply enjoying your favorite activity on the water. Thermo-X offers a reliable fit, fresh modern style, and the trusted O’Neill quality that’s built to last.

Color: Black


Swimwear Form Type: Rash Guard


Sleeve Type: Short Sleeve


Style Name: Men's Thermo-x S/S Crew


Swimwear Top Form: Rash Guard Top


Rise Style: Low Rise


Pattern: Solid


Neck Style: Crew Neck


Apparel Closure Type: Pull On


Strap Type: Pull On


character: sports


Fit Type: Snug


Material Type: Nylon, Spandex


Product Care Instructions: Hand Wash Only


Fabric Type: Other Fibers


Apparel Fabric Stretch: High Stretch


Apparel Fabric Weight Class: Medium Weight


Sleeve Length Description: Short Sleeve


Fit to Size Sentiment: Positive


Product Benefits: Provides UPF 50+ Sun Protection and Warmth with Quick-Dry Fabric


Brand Name: O'NEILL


Special Size Type: Standard


Age Range Description: Adult


Style Number: 5021


Global Trade Identification Number: 80


Import Designation: Imported


UPC: 191015009680


Number of Items: 1


Included Components: wetsuit


Item Type Name: Rash Guard


Manufacturer: O'Neill Wetsuits


Manufacturer Part Number: 5021-002-L


Unit Count: 1 Count


Manufacturer Warranty Description: GENERAL WARRANTY INFORMATION AND POLICY If the product is found to be defective under normal use and proper care, O'Neill Wetsuits will repair or replace, at O'Neill Wetsuits' option. This decision to replace or repair is made by the O'Neill Wetsuit Warranty Department after receipt of the defective product. At no time does O'Neill Wetsuits offer refunds. For more information, go to


Ultraviolet Protection Factor: UPF 50+


Garment Size Country: United States


Size: Large


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Sunday, Oct 18

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Works extremely well; buy one size up
Size: Large Color: Black
This shirt is one of my favorite purchases that I’ve made in a long time. It is a total game changer if you are sensitive to cold water, even when swimming indoors in the winter time. I no longer have to give myself a peptalk to go to the pool. I do a deep water workout that is very vigorous, but because I have spine issues, the cold water can cause my muscles to seize up. Not anymore, however. This really really keeps me warm from the second I jump into the pool until I get out 50 minutes later. Some people complain that it is difficult to take off when it is wet. However, there is a method that works really well. First remove one arm, then remove the other arm and then lastly pull it over your head. If you try to pull it over your head when it’s wet without taking your arms out, it’s impossible, but this method that I use works very well. ... show more
Reviewed in the United States on December 31, 2024 by ted davis
    • This magic fabric is awesome!
Size: Small Color: Black
I don't know what kind of voodoo magical material this is, but I'm glad I found it. It's like wearing a very lightweight sweatshirt in the water. Typical rash shirts are nylon and cold when you put them on, cold when you get out and the wind hits you, and can be heavy even after you've wrung the water out of them. THIS feels like a warm cloud when you first put it on and keeps me warmer than a standard rash shirt when swimming in the pool. When you take it off afterward, it is really heavy and you think, "I'm gonna need a wagon to bring this home," until you wring it out, and then, as if by some Hogwarts magic, it's lightweight and feels almost dry. I'm 5'7"", 145 lbs and got a small. It's very tight but doesn't impede movement in the water. Like a fuzzy, warm extra skin. I might have to do something crazy like buy 10 more in case they stop making them. ... show more
Reviewed in the United States on October 13, 2024 by Oma 2 Three
    • Perfect for the beach
Size: X-Large Color: Black
This really works. Keeps you warm both underwater and out of the water, while being breathable and fitting like any rashguard. Not quite as warm as say 2mm neoprene but close, and its breathable, thus comfortable in and out of the water. Can be worn under neoprene wetsuits as well, for an added layer of warmth. But I've used it mostly to stay warm at the beach for body surfing etc when the temperatures aren't quite high enough to be comfortable in the water without some form of insulation, but not cold enough to require the inconvenience of a shorty wetsuit. Due to its breathability, this would also be a great safety undergarment for cold weather boating/fishing activities. Its warm and breathable and if you accidentally fall in it would provide a decent amount of insulation to help slow the onset of hypothermia. ... show more
Reviewed in the United States on August 29, 2024 by Peter
    • Size up, bunches in the armpits
Size: Medium Color: Black
These O'Neill tops are all sized too small. Fabric bunches in the armpits. Neck hole is small and hard to get head through. Also, would be nice if the hem were longer - may ride up. Consider the O'Neill Hyperfreak neo rashguard hybrid, which is longer in the body, more comfortable in the armpits, warmer in the back and chest (1mm neoprene), but cooler in the flanks and arms (Nylon/Spandex). ... show more
Reviewed in the United States on November 1, 2024 by Amazon Customer
    • Where has this material been?
Size: X-Large Color: Black
Definitely my new favorite water top. The outside feels similar to most rash guard material, the inside feels like a cross between microfiber and soft felt. It comes together as softer and more stretchy than rash guards or neoprene. It does not form a water tight barrier like neoprene, but restricts flow and provides better warmth and cushion than rash guards. Because it is so flexible and the inside resists sliding across the skin, It is great to reduce chaffing under the arm or around the neck when warn under a wetsuit, PFD, or BC. I bought it for whitewater kayaking and its perfect, but I can tell I will also be using it for surfing and scuba diving, both as a stand alone top and worn under a wetsuit depending on the temp. Good job O'Neill! ... show more
Reviewed in the United States on May 19, 2024 by WDL
    • I think these are kids sizes.
Size: XX-Large Color: Black
Excellent material and quality however, the size is way off even an extra extra large fits like a small.
Reviewed in the United States on June 7, 2025 by Patrick m.
    • Unbelievably good
Size: X-Large Color: Black
This is absolutely amazing, what a great idea from Oneill guys. Extremely lightweight and warm, protects against the wind very nicely too. Definitely a go, one of best surfing gear I’ve ever gotten . I think it runs just a bit small.
Reviewed in the United States on November 17, 2024 by Amazon Customer
    • The material expands .once it is wet
Size: Small Color: Black
I bought a medium and later bought a small medium fits loose once it’s wet, but the small is very difficult to get on and off. A small body doesn’t mean a small head. Neck should be made a little larger.
Reviewed in the United States on January 31, 2025 by E. LeTourneau

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