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CastelliFlanders Warm Long Sleeve Base Layer - Women's

Sale 50% Off$39.97 $79.95

Item # CST004B

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Item # CST004B

Keep warm and keep riding.

There are countless weather problems that every cyclist has to prepare for during the fall, winter, and spring. For rain, you'll want a rain jacket that doesn't make you overheat. For chilling wind, you'll need a wind blocking jersey, instead. If choosing the appropriate outerwear is among the most important decisions a cyclist can make in the colder months, then choosing the right base layer isn't far behind. Happily for us, when the temperature drops to 10 degrees Fahrenheit either side of freezing, then this second choice is easy: Castelli's Flandria Warm Base Layer with Long Sleeves.

The Flandria is made with a durable SottoZero Fleece that insulates and wicks. Dryer, after all, is warmer. Mesh inserts provide ventilation in the underarms, just in case you overheat, and the flatlock stitching and flat hems mean the Flandria will fit comfortably as a piece of layering gear. Castelli recommends it for use in 23 to 46 degrees, and, while this range may seem excessively broad, we find that the Flandria gets the job done in all conditions when layered with the right outer layer.

The fit is snug and long, with an exaggerated hem and sleeves to ensure no gap in coverage between top and bottom, gloves and cuffs. It's snug enough that you can wear it however you need it: under a jersey in the low 40s, under a jacket in the low 30s, under rainwear — whatever the situation calls for. The Flandria Warm's branding is less ostentatious than the basic Flandria jersey, comprising only a simple, non-stylized Castelli with no red scorpion logo. Chances are good that, if conditions call for the Flandria Warm, you'll likely keep your jacket or outer jersey zipped up the entire ride. The Flandria Warm isn't for showing off, it's purely for keeping you warm; however, it will let you accumulate base miles through the coldest months so that, come spring, your legs will be doing all the talking.

  • An insulating layer to tackle frosty days
  • SottoZero fleece traps heat in, wicks moisture away
  • Let sweat escapt with mesh inserts at underarms
  • Avoid chaffing with help from flatlock seams
  • Snug and long fit makes for perfect layering under jersey
  • Castelli recommends for temps 23-to-46-degreed Fahrenheit
Tech SpecsSize
Tech Specs
SottoZero Fleece
Recommended Use
Manufacturer Warranty
1 year


Women's Apparel












































Note: Castelli has a "Euro" slimmer fit. We suggest ordering at least one size larger than your normal US size.
How to Measure:
For best results, take measurements over your underwear.
Measure under your arms, around the fullest part of your chest.
Natural Waist:
Measure around your natural waistline, keeping the tape a bit loose.
Measure around the fullest part of your body at the top of your legs.
Using pants that fit well, measure the crotch seam to the bottom of the leg.

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Good weight

  • Familiarity: I've used it several times
  • Fit: Runs small
  • Size Bought: large

LIght weight, but well fitted close to the skin, kept me warm but not too hot in the winter
Perfect for 33 F to 40 F temps under jersey

Fit very tight at the chest and arms

  • Familiarity: I gave it as a gift but have feedback to share

Bought this for my daughter as a Christmas gift. She is between a small and medium top. This was way too tight in the arms and shoulders. I'm a completely different body type and typically wear a medium. I tried it on and I too had trouble with the shoulders and arms. A large I believe will be too big everywhere else so I returned it. Return was very simple.

Favorite Base Layer

  • Familiarity: I've used it several times

This base is now my favorite for any activity. It's so soft and is freakishly warm without being heavy. I can wear only this with the Gabba jacket and be good in single digit (Celsius) temps. Last weekend I was actually colder when I added a layer. I think it's because I wasn't as dry. It's so good I bought one for my boyfriend and he loves it too. Such a great addition to cold weather riding.

Warm winter essential

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: XS

This is a great warm, form-fitting, wicking baselayer. I have another baselayer, different brand, which provides wicking, but the fleece and warmth of this piece goes beyond that. I have worn this baselayer, bibs, and the Castelli women's Alpha jacket road riding in temps between 30 and 40 F. and have been very pleased with the warmth and wicking as well as the extra length. With a second fleece layer, the Flandria has wicked and held in warmth well below 30 degrees F. For winter MTB, it's also an essential. It has held up well in daily garment bag, gentle cycle washing, and maintains its form fit. I bought an xs which fits great under the Castelli Alpha small.

Warm, thin and stylish

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: Medium

This base layer is warm, soft, fitted and stylish. It's thin and fits nicely under a jacket. I live in Arizona and the winters get cold. This base layer keeps me warm without being too bulky.

Best Base Layer I Own

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: large

the body and arms of this is sooo soft and even though it isn't thick, it does the job of keeping you warm! The under arm material is great as well, I have yet to sweet in this, it's like they know where to vent and again, the thin material is amazing. I ride 2+ hours in below freezing temps and my body is perfect with this and the Castelli Alpha Jacket.

I like this

  • Familiarity: I've used it once or twice and have initial impressions
  • Fit: True to size
  • Size Bought: Medium

Nice top - warm and comfortable. The small was too small so I returned for a Medium. I wish the Medium was a tighter fit in the waist area but otherwise it's great.