A steel-toe boot (also known as a safety boot, steel-capped boot or safety shoe) is a durable boot or shoe that has a protective reinforcement in the toe which protects the foot from falling objects or compression, usually combined with a mid sole plate to protect against punctures from below. Although traditionally made of steel, the reinforcement can also be made of a composite material, a plastic such asthermoplastic polyurethane (TPU) or even Aluminum. Steel-toe boots are important in the construction industry and in many industrial settings. Occupational safety and health legislation orinsurance requirements may require the use of such boots in some settings, and may mandate certification of such boots and the display of such certification directly on the boots. In Canada, certified boots have a Canadian Standards Association green triangle on them. Safety footwear now comes in many styles, including sneakers and clogs. Some are quite formal, for supervising engineers who must visit sites where protective footwear is mandatory. Some brands of steel-toe footwear, particularly Dr. Martens and Grinders, have become fashionable within subcultures such as skinhead, punk, and rivethead. While brands that were previously renowned within the fashion industry have also diversified into the safety footwear market, industrial brands like Caterpillar, Rock Fall and JCB have also given out licenses to produce safety footwear