The Alphaburly® Sport Side Zip is made of ozone-resistant,scent-free, rubber-clad neoprene for lightweightcomfort and 100% waterproof protection. It features anexpandable gusset and side-zip to accommodate largercalf sizes and the LaCrosse® Ankle-Fit? design for asecure fit. With 1200 G. Thinsulate? Ultra Insulation,a Sport Chassis? outsole and EVA midsole, this bootprovides all-day comfort in cold temperatures, on variedterrain.