X-treme Performance. X-treme Comfort. X-tremely Lightweight. The Carbo-Tec LTX collection has the incredible durability and performance features of the Carbo-Tec LT outsole built with a more aggressive tread pattern to take on the most rugged job environments. A padded counter pocket locks your heel in place to provide added support and comfort. Built with heavy duty performance and a lightweight feel, the Carbo-Tec LTX boot will keep your feet comfortable through any job, big or small.