Trying to choose between a heavy jacket and your standard cool weather jersey-and-warmers combo gets old fast, especially after you've chosen incorrectly a few times and wound up with stiff, frozen arms or spent an entire ride soggy and overprepared. Rather than trust your own weather assessments, brave the volatile shoulder seasons in Castelli's Gabba 2 Short-Sleeve Men's Jersey. Wear it with Castelli's Nanoflex Arm Warmers when the weather takes a turn for the worse, and you'll stay warm and able to breathe in windy and wet conditions. To strike that difficult balance, Castelli crafts the Gabba 2 using Windstopper X-Lite fabric, a lightweight, breathable synthetic engineered to block icy gusts while still allowing sweat to evaporate at its surface so you stay cool. It's also treated with a water-repellent finish so that surprise rain showers don't leave you saturated, and Nano Flex inserts along the underarms add ventilation and breathability to a more sweat-prone area. According to Castelli, the Gabba 2 works best in temperatures ranging from 50 to 64 degrees Fahrenheit, but your comfort will ultimately depend on how hard you're riding and how you choose to layer. And don't be alarmed to find the Gabba 2 fitting tight across the chest and shoulders when you first stand up in it; Castelli does this on purpose to guarantee its kit follows your body position perfectly once you're in the saddle.