With the changing leaves and air as crisp as a new crop apple, fall is one of the best times to ride a bike. But it can also be chilly, especially if your schedule doesn't always allow you to wait for the warmest part of the day. To address this, we turn to Castelli's Flanders Warm Half Zip Base Layer. While we're not sure if the name means that it's as warm as Flanders which... what' or if it means that it's warm enough to wear while cycling in Flanders more likely, we do know that it fends off cold like Museeuw fended off late stage attacks in the race of the same name. The Flanders Half Zip is comparable to its non zip sibling in every respect except for the zipper. It's made with the same durable SottoZero Fleece that insulates and wicks, and includes the same mesh inserts in the underarms. The flatlock stitching and flat hems mean the Half Zip will fit as comfortably as the non zip. Castelli recommends it for use in 23 to 46 degrees Fahrenheit, and, while this range may seem excessive, we find that the Flanders gets the job done in all conditions when layered with the right outer layer. The Castelli Flanders Warm Base Layer Men's is available in six sizes ranging from X Small to XX Large in the color Grey.