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Castelli Seamless Men's Base Layer

Sale $43.99 $54.95 20% off

Item # CST2599

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  • White, S/M ($43.99)
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Item # CST2599

An essential.

Don't make the mistake of thinking a base layer is a luxurious extra you can take or leave. Sure, it's not as essential something like a helmet, but the right one can make a pretty significant difference in your ride comfort. Grab Castelli's Seamless Men's Base Layer to see what all the fuss is about and pair it with a regular jersey on warm days and your thermal jersey on colder ones. It'll keep moisture moving away from your skin quickly as you sweat, while acting as a breathable insulating layer during colder days. Castelli uses a blend of nylon and polypropylene fibers to achieve this, cut in a form-fitting silhouette that will mimic your body movements in the saddle. The closer it fits, the better it works. Castelli added a few strategic mesh panels throughout to usher in extra airflow, while knitting the fibers in an open weave to ensure you get consistent ventilation as you ride.

  • Synthetic base layer moderates temperature and wicks moisture
  • Insulates in cold weather, cools in the heat
  • Contoured, next-to-skin fit for efficiency
  • Mesh panels facilitate airflow

Tech Specs

Material:
[inner-layer] polypropylene, [outer-layer] nylon
Fit:
form-fitting
Style:
crew
Recommended Use:
cycling
Manufacturer Warranty:
1 year

Size chart

Castelli

Men's Apparel
 Small Medium Large X-Large 2X-Large 3X-Large
Chest  35.5 - 37in
(90.2 - 94.0cm)
37 - 38.5in
(94.0 - 97.8cm)
39 - 41in
(99.1 - 104.1cm)
41 - 43in
(104.1 - 109.2cm)
43 - 45in
(109.2 - 114.3cm)
45 - 47in
(114.3 - 119.4cm)
Waist 29.5 - 31.5in
(74.9 - 80.0cm)
31 - 33in
(78.7 - 83.8cm)
33 - 35.5in
(83.8 - 90.2cm)
35.5 - 37.5in
(90.2 - 95.3cm)
38.5 - 40.5in
(97.8 - 102.9cm)
41 - 43in
(104.1 - 109.2cm)
Hips 36.5 - 38.5in
(92.7 - 97.8cm)
38 - 40in
(96.5 - 101.6cm)
40 - 42in
(101.6 - 106.7cm)
42 - 44in
(106.7 - 111.8cm)
44 - 46in
(111.8 - 116.8cm)
46 - 48in
(116.8 - 121.9cm)
Inseam
31.5in
(80.0cm)
32in
(81.3cm)
32.3in
(82.0cm)
32.8in
(83.3cm)
33in
(83.8cm)
34.8in
(88.4cm)
How to Measure:
For best results, take measurements over your underwear.
Chest:
Measure under your arms, around the fullest part of your chest.
Waist:
Measure around your natural waistline, keeping the tape a bit loose.
Hip:
Measure around the fullest part of your body at the top of your legs.
Inseam:
Using pants that fit well, measure the crotch seam to the bottom of the leg.

Reviews & Community

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Avg. ride time: 6h 32m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Might be my favorite piece of kit

  • Familiarity: I've used it several times
  • Fit: True to size

I have both this and the other Castelli mesh baselayer, and while they cost about the same amount, this one is head and shoulders above its sibling. The material is much thicker, stretchier, and more substantial. I find this type of mesh baselayer keeps me cool on hot rides and warm under my kit on cold rides, so I wear one on essentially every ride. I also think it takes the brunt of the sweat, and as such I feel like I can wash my jerseys less often, which lets them live a bit longer. All-in-all, this is my concept of the perfect baselayer and I could not recommend it more highly. Other comments are accurate, when you take it out of the box it will look like it was made for a small child...trust me, it stretches.

Great baselayer for warm temps.

  • Familiarity: I've used it several times
  • Fit: True to size
  • Size Bought: L/XL

A great base layer for warm to hot days. It is well made and comfortable -- and creates a bit higher layer than the similar mesh base from Castelli. I like how this piece prevents chafing and keeps me cool. It is well made too and holds up in the wash, though I usually use a garment bag to keep it safe.

Avg. ride time: 6h 8m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Makes all the difference

  • Familiarity: I've used it several times

I was skeptical that a baselayer could be used effectively under a jersey in both cold and dry temperatures, and I am so happy that this skepticism was wiped away. This undershirt keeps the jersey off of your skin and wicks away sweat so well that you never get that "wet jersey" feeling on those long hot rides. On the other side, when it's cold outside, it keeps that layer of warm air close to you thanks to the "unique" fishnet design. I will not be riding without this and may buy a second at this price point.

Buy this

    Castelli offers arguably the largest lineup of pro & performance cycling clothing made in the sport. The experience, detail, and 'know-how' that Casteli puts into their gear is pretty amazing. This is seen for example in Castelli's lightness glove, climber's jersey, Mortirolo jacket, and even their cycling socks.



    This "seamless" baselayer is designed to be used in -warm- weather. It is made with special moisture transfer fabrics. It is also designed with "open mesh" construction to hold your jersey off your skin. These features promote moisture transfer, sweat evaporation and cooling. It works!



    Every serious rider should consider using a baselayer like this in warm weather.

    A micro-climate for your core!

    • Familiarity: I've used it once or twice and have initial impressions

    I'm a big believer in technical undershirts for low temperatures on up to about 80 degrees F. Beyond 80 in a low humidity environment I can't see much benefit over having a good quality jersey against my skin, but there are situations where it could still be helpful. This undershirt is perfect for the temps I've been riding in lately, 45 to 65 degrees. It creates a nice layer of trapped air while efficiently moving moisture away and keeping me dry with a stable core temp. It's very mesh like, and given it's stretch the sizing is very forgiving. It has a nice long torso and lays flat against your skin. It will look very small when you pull it out of the box. My wife laughed when she saw it and insisted I never let anyone see me in it! So of course I made it a point to walk around the house in it! My only complaint is that the material will snag easily. Use caution if you're wearing a watch when you put it on, and perhaps, be willing to accept that you'll get some snags that widen some of the mesh openings over time.

    Totally Awesome Base Layer!

    • Familiarity: I've put it through the wringer

    Unbelievable fabric & mesh design. Wicks better than any other base I've used in the past. Ideal for hot days too! It keeps a dry (not clammy) layer against your skin thus keeping you comfortable on hot days. Wicks moisture to outer jersey where it evaporates. I love this base. I am 5'7" @ 165lbs. chest 40" and a lg/ex lg. size fits snug like it was designed to fit for maximum efficiency.

    Avg. ride time: 3h 57m per week
    • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

    awesome base layer!

    • Familiarity: I've put it through the wringer

    The large seem small but stretches for a nice fit. it is very comfortable and warm but not hot. The mesh is like magic and keeps me dry.

    Avg. ride time: 6h 43m per week
    • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

    Awesome Base Layer

    • Familiarity: I've used it once or twice and have initial impressions

    This base layer did exactly what I was hoping it would do. It helps me maintain an even body temperature in various Fall climates and keeps my jersey from getting sweaty and cold against my skin. It works well for me in temps from mid 50 degrees to mid 80 degrees, but I have hopes that I can use this base layer year round. Very impressed with the quality as well. I can barely tell it's on when I wear it. One note, when you get first pull it out of the box it will be tiny like a child's shirt. I'm 5'10' 150lbs. and the S/M fits perfect.