Sportful's team of captive scientists err, willing and hardworking researchers, we mean spent months hidden away in their underground lab researching and constructing the RD Long Sleeve Wind Jersey. Fabrics this technically advanced don't just come together naturally, so we're grateful that the team put in the time and effort to make the RD one of the most advanced wind jerseys out there. It's meant for riding in cool fall weather, but if you layer properly the RD will work well as a winter layer, too. Polartec Alpha fabric at the front cuts the wind and traps heat, while the WindShield panel at the rear prevents gusts from blowing over your shoulders and sucking the warmth away from your back, which is actually where most wind induced heat loss occurs. Both fabrics wick moisture extremely efficiently, and are complemented by stretch mesh side panels that increase breathability and mobility. The eggheads at Sportful are clearly cyclists themselves, because there's no other explanation for the RD's nearly perfect array of details, like three large stretchy back pockets that sit on an independent panel to increase support or the generous thumb loops that seal in heat and seal out drafts. A wind flap covers the YKK Vislon zipper to complete the windproofing, and an additional side pocket provides secure storage and easy access to key items like phones. Reflective rear details add safety to your low light rides, and a silicone gripper elastic at the waist locks the RD in place so you don't expose skin.