For those first cool fall days or the last remnants of spring, the Pro Thermal Mid LS Jersey gives you some extra warmth. The secret is in the fabric. Compared to our standard Warmer fabric, we've lightened it up a touch and added some spandex/elastane for more stretch. It has a close-to-body aero fit without feeling too tight. It's a performance piece for every ride, with our drop-pocket construction and YKK® Vislon® zipper for easy one-handed adjustment. Why would you want a less warm thermal jersey? One situation is in conditions that are too cool for a short-sleeve jersey and it just feels better to cover up and add this bit of warmth. Another situation is a higher-intensity ride where it's easy to overheat. In keeping with the pro technical function of this jersey, we've kept the design details very clean, with an embossed stripe across the chest and a reflective vertical stripe on the pocket for low-light visibility.