Bontrager's RXXXL Bib Shorts are pro-level in form, fit and function. The main body is crafted from ultralight, soft, breathable Profila Power compression fabric for muscle support and superior aerodynamics. No-sew bib straps are super smooth for zero chafing and they sport mesh panels on the back and stomach for extra ventilation. For the ultimate in comfort, these bibs use an inForm RXXXL chamois, with 4-way stretch and an anti-microbial top sheet. And, the Pro Fit of these bibs provides second-skin aerodynamics and a clean, streamlined contour.