Infinity means forever. That's about how long your feet will feel comfortable in this boot. Wherever the site, whatever the job, Infinity FD delivers modern boot amenities and traditional Thorogood reliability that doesn't compromise comfort for performance. The patent pending Flex-drive rear-welt construction allows for maximum flex in the toe and superior construction. Paired with FLEX-DRIVE is our proprietary Anti-Fatigue high rebound sole that returns energy with every step. The combination of these two technologies delivers a relentless level of comfort and performance. With zero break-in and weather defiant protection from the elements, the Infinity FD gives you peace of mind, comfort, and confidence so you can focus on a job well done. Studhorse full-grain leather. Waterproof. Removable, single-density, anti-friction polyurethane footbed. Composite shank. Multi-traction, self-cleaning, Infinity FD FLEX-DRIVE outsole. 51% welt construction.