Amazon.com | RefrigiWear Men。Comfort Rating: -40°F to 10°F RefrigiWear® Hybrid Traction outsole The BOA® Fit System for micro-adjustable fit that won\'t come loose Dial into fast, effortless, precision comfort and warmth with the Extreme Hiker Boots featuring the BOA® Fit System. When you\'re working in extreme cold conditions, you don\'t want to take your gloves off to adjust your boots. With the BOA® Fit System, you don\'t have to. Use the dial to tighten and loosen without compromising hand protection and get the perfect fit, that lasts all shift. Keep out extreme winter weather with our HYDRY® waterproofing sytem. These cold-weather work boots have a waterproof 8-inch nylon and leather upper and these winter work boots fight fatigue with VitaComfort®, which absorbs the shock to your feet from walking and standing all day. Each boot has an ASTM composite safety toe, RefrigiWear® Hybrid Traction outsoles, and rubber heel plates for added protection and extra durability.