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Specialized Seamless LS Baselayer



Very warm, comfortable synthetic winter base for the coldest rides
Particularly warm
Good moisture management
Odour resistant
Quite long sleeves
Shortish torso
Probably too warm for spring and autumn

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The Specialized Seamless LS is a relatively thick, very warm baselayer that's best for when temperatures are under 5°C. It's comfortable against the skin, wicks really well and the fit is good – it's also competitively priced.

Staying warm – without just boiling over in your own sweat – makes a huge difference to whether winter miles are enjoyable or just a real slog. This Specialized base is thicker than most, and ideal for the coldest of winter rides.

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The seamless design and flat-locked stitching make it very comfy, with nothing to rub even when you're layered up and/or wearing a pack. I'm particularly fussy when it comes to baselayers with sleeves, as poorly fitting ones can gather or pinch at the arm pits, and I can happily report that this one caused no discomfort.

Most importantly, it's warm! Despite an abundance of similar bases in my drawer, more often than not this has been the first one out for rides under 5°C, as it often means you can ditch a midlayer and just pair it with a jacket.

2021 Specialized Seamless LS Baselayer - back hem.jpg

The attention to shaping across the slim fit is very good, and various patterns of knit keep it snug all over with no overly tight or baggy bits. It has a good, comfortable stretch, and the sizing feels accurate. The sleeves are quite long compared to the body, though, which may not suit if you have a longer torso or bigger gut.

2021 Specialized Seamless LS Baselayer - hem.jpg

The medium-high collar provides ample protection against drafts without being too intrusive – a potential problem on the high-necked likes of the (more expensive) Spatz BASEZ 2 baselayer.

2021 Specialized Seamless LS Baselayer - shoulders.jpg

The Specialized is also excellent at wicking sweat considering its thickness; the different fabric styles for the armpit and back sections help here. It's also remarkably good at resisting smells – I wore this unwashed for five successive rides, often under not very breathable waterproof jackets, and it did very well!

> 16 of the best cycling base layers for riding through the year

Washing instructions are printed on the bottom cuff should you nearest and dearest finally stage an intervention, which means no annoying labels. Overall it feels made to last, too – it's survived plenty of washes with no loose threads.


At £55 it's not badly priced either. That's still a lot to shell out on a baselayer, but the Megmeister Drynamo Winter LS is £10 more at £64.95 and hard to distinguish, performance-wise, from this.

The dhb Aeron Polartec also performs very well, but even that is now £50 (up £10 since our test 11 months ago), while many make the Specialized look a positive bargain; the Santini Grido, for example, will set you back £120. Whilst it's very good, this thing will get you 99% of the way there for a lot less.


This baselayer does exactly what it promises to, and to a very high standard. It feels good against the skin, breathes well and retains useful warmth. I'd happily choose this synthetic offering over a merino alternative, and the price is competitive as well.


Very warm, comfortable synthetic winter base for the coldest rides test report

Make and model: Specialized Seamless LS Baselayer

Size tested: S/M

Tell us what the product is for

Specialized says: "Form-fit underwear made of moisture moving fabric."

Tell us some more about the technical aspects of the product?

58% Polypropylene, 38% Polyamide and 4% Elastane

Available in 3 sizes: S, M/L and XL/XXL

Prolen Yarn

Rate the product for quality of construction:
Rate the product for performance:

Very warm on the coldest rides and wicks sweat well. Not for mild days though, due to being thicker than most.

Rate the product for durability:

Very well made.

Rate the product for fit:

Long sleeves and relatively short in the torso, which could be a problem for those with beer bellies that require some extra material.

Rate the product for sizing:

Sizing seems accurate.

Rate the product for weight:

It's quite weighty, but offers appropriate insulation.

Rate the product for comfort:
Rate the product for value:

How easy is the product to care for? How did it respond to being washed?

No issues.

Tell us how the product performed overall when used for its designed purpose

Very well; it's comfortable layered up or under a pack, and retains warmth well.

Tell us what you particularly liked about the product

Warm and comfortable.

Tell us what you particularly disliked about the product

Nothing really.

How does the price compare to that of similar products in the market, including ones recently tested on

As mentioned in the review it's reasonably priced against the competition, and it marginally outperforms some more expensive baselayers.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

This is very good: warm, comfortable and a good fit. The thickness and warmth does limit it slightly to the coldest months, but if that's what you need, it's great.

Overall rating: 8/10

About the tester

Age: 23  Height: 6ft  Weight: 74kg

I usually ride: Specialized venge pro 2019  My best bike is:

I've been riding for: Under 5 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, club rides, sportives, general fitness riding, mtb,

Jamie has been riding bikes since a tender age but really caught the bug for racing and reviewing whilst studying towards a master's in Mechanical engineering at Swansea University. Having graduated, he decided he really quite liked working with bikes and is now a full-time addition to the team. When not writing about tech news or working on the Youtube channel, you can still find him racing local crits trying to cling on to his cat 2 licence...and missing every break going...

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