Castelli was an early pioneer of water-protective thermal fabrics, having recognized just how beneficial they are for cycling applications. Don't assume these knee warmers are exclusively for rainy rides on wet roads, however, as the water-repellent fabric is also highly breathable, making them a great option for cooler dry days, too. The best part is if the sun comes out, you can easily slip them off and stow them in a jersey pocket, unlike knickers and full-length tights.