If you ever wish your bike shorts could magically grow to cover your knees when it gets cold, or that your pants could shrink up for spring riding, grab the Castelli Thermoflex Knee Warmers. These stretchy fleece warmers cover your knees, so you can pair them with your riding shorts on chilly days. Elastic on the cuffs of the Thermoflex Knee Warmers gives them a solid fit, while Castelli's scorpion logo adds eye-catching detail.