Upon initial inspection, it's clear that the Nano Shoe Covers are first and foremost intended to smooth the airflow over your bumpy, ratchety shoes. But once you start wearing them, you'll realize that they serve so many more purposes. Made from silicone coated Lycra, they keep you aero and actually protect your feet from the wind. The material also forms an effective barrier to the rain and cold so that you can wear these with confidence for your weekly time trial series and drizzly, gloomy October afternoons alike. In fact, if you have a warm enough sock, you can wear these babies in everything but the coldest conditions.