4XLT - This R.B.I. 1/4 zip convertible windshirt features a shell constructed of windproof/water resistant mini-ripstop polyester. Zip sleeves off to turn into a short sleeve. Inner short sleeve birdseye mesh knit panels feature UltraCool (R) moisture wicking technology. Constructed with front pockets, elastic bound cuffs and draw-cord bottom hem for a custom fit. Contrast sleeve panels and front piping provides a sporty look.