Details
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.
Key features:
- Profila Cool fabric powered by 37.5 active particle technology
- Conditions-appropriate, tuckable length
- Drop tail for a precise on-bike fit
- Fitted cut provides streamlined body fit for enhanced performance
Features

B1 Sleeveless Women's Baselayer
An ultralight, cooling sleeveless baselayer for women that provides warm weather comfort.

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

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 wardrobe
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.
Part Numbers
Option | UPC | MPN |
---|---|---|
White / X-Small | 601479536986 | 540510 |
White / Small | 601479536993 | 540511 |
White / Medium | 601479537006 | 540512 |
White / Large | 601479537013 | 540513 |
White / X-Large | 601479537020 | 540514 |