The Pearl Izumi P.R.O. Thermal Bib Knickers are based around the best qualities of the P.R.O. Bib Shorts, with the added advantage of being thermally insulated and designed to keep your knees toasty warm. If you count up the number of days you ride a year, you'll be surprised at how many of those rides take place cool to cold temperatures. Though some people can withstand colder temps than others, it is generally a good idea to start covering up your knees around the 50 to 55 degree threshold. Your knees ? especially when they get to be middle aged ? will thank you. The P.R.O. Thermal Bib Knickers are made from Pearl Izumi?s P.R.O. Thermal MicroSensor fabric which is a luxuriously soft material that's designed to keep you warm by regulating your body temperature and wicking away any moisture caused by sweat. With a 17 inch inseam, the knickers? legs are cut to extend midway down your calf. This is intended to give your knees enough coverage to keep them warm without extending so far down the leg that you'll have a bothersome gripper cuff on the most muscled part of your calves. The bib upper is made from a four-way stretch MicroSensor mesh which offers a touch of insulation for your torso while also providing a moisture wicking benefit. The 4-way stretch allows the uppers to flow with you like a second skin. Most exciting is that these knickers come with the Anatomic P.R.O. Seamless Chamois. This chamois probably gives the most consistent all day comfort of any Pearl Izumi pad. It's designed with four different layers of varying densities depending on the most important pressure points. Its Ultra 3-D anatomic shape means that it is pre-shaped and curved to suit the natural build of the rider. The fact that it is also seamless means that there will be no strange chafing spots that start to irritate you three hours into the ride. Rather, the four-way stretch technology will make sure that the pad moves and breathes with your every pedal stroke. Pearl Izumi wants to make sure that you're super comfy, especially on those long and cold base mile rides. The Pearl Izumi P.R.O. Thermal Cycling Bib Knickers are equipped with reflective elements to keep you visible even when the street lamps are coming on. They come in Black and are available in sizes Small through XX-Large.