Riding a bike has been scientifically proven to be the most effective method of wind generation, so you'll want to don the Gore Bike Wear Oxygen WindStopper Active Shell Men's Vest even if high speed pedaling is more likely than blustery climbs. The Oxygen is incredibly lightweight but engineered with a nearly gust proof WindStopper membrane to shelter your core from the vagaries of spring and fall weather. It's also finished with partially covered shoulder seams to improve protection from drizzle and light rain in the most exposed areas. Weather resistance doesn't have to be bulky, either. The WindStopper membrane is exceptionally thin, as is the nylon fabric, so you can fold the Oxygen up and stuff it into its own zippered front pocket for easy packing, even into a jersey pocket. Slide down the semi locking front zipper for extra ventilation when the wind dies down and the sun pops out, and ride home in comfort knowing that the reflective details will help prevent oblivious motorists from running you into the gutter.