Castelli belgian bootie 4 this is one of those products that just works it adds a little bit of warmth but no weight or bulk and is surprisingly good at keeping road filth of your sidis or bonts when the mercury plummets they add an extra layer of insulation under your more serious shoe covers featuring reflective stitching for road safety and sleek pro style the castelli belgian bootie 4 must be the cheapest pro cycling accessory available features 100 polypropylene construction for ea