Composite Safety Toe. Identifies protection against impact and compression hazards with a composite (non-metallic) safety toe. Composite toes meet ASTM F2413-18 standards. Electrical Hazard (Safety Toe). Identifies secondary protection against incidental contact with electrical circuits of 18,000 volts or less under dry conditions. Safety Toe EH styles meet ASTM F2413-18 EH standards. Insulation (400gm 3M Thinsulate) These shoes are designed to keep your feet warm in most types of cold conditions. 3M Thinsulate is a microfiber that insulates boots by trapping air molecules between you and the outside. 400 grams is used for cold conditions or moderate activity levels. Storm Defender Waterproof Breathable Protection. These shoes are designed to be completely waterproof and to keep your feet dry in most types of wet conditions. A waterproof and breathable membrane is used to keep your feet dry but promote air flow and circulation. Cushion Comfort Insole. Carhartt PU with Foam cushion insole provides comfortable support and reduces foot fatigue.