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Secretly cool

Even warmer rides can benefit from the right baselayer. Bontrager's lightest weight baselayer fabric, B1, is a comfortable first layer of Profila Cool fabric enhanced with 37.5 technology that regulates the body’s relative humidity to maintain ideal core temperature, allowing greater on-bike performance. Comfortably fits under every jersey you own.

Product details

  1. Profila Cool fabric powered by 37.5™ active particle technology
  2. Conditions-appropriate, tuckable length
  3. Drop tail provides a precise on-bike fit
  4. Fitted cut provides streamlined body fit for enhanced performance

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B1 Sleeveless Women's Baselayer

B1 Sleeveless Women's Baselayer

An ultralight, cooling sleeveless baselayer for women that provides warm weather comfort.

Cycling-specific fabrics

Cycling-specific fabrics

Profila fabrics are designed to wick moisture rapidly and dry quickly for superior breathability to keep you comfortable.

Maximum breathability

Maximum breathability

37.5 fabrics push moisture to the outermost layer of clothing for rapid evaporation. When you use less energy to regulate your temperature, you have more energy for riding.

Streamline your wardobe

Streamline your wardobe

A fitted cut provides streamlined body fit for enhanced performance and a next-to-body silhouette. If you prefer a roomier cut, size up on this garment.

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Gender Women
Fit profile Fitted
Fiber content 66% Polyester / 19% Cocona® 37.5® Polyester / 15% Spandex
Material Knit
Sleeve length Sleeveless
We reserve the right to make changes to the product information contained on this site at any time without notice, including with respect to equipment, specifications, models, colors, and materials.
Weights are based off Trek pre-production products at time of publication. Weights may vary in final production.

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