Caribou II Boots Caribou II Boots are waterproof, featuring wheat nubuck leather uppers and PVC UniTrack lug outsole design. Combrelle® lining, Cambrelle® covered cushion insole, 400 gram Thinsulate™ Ultra Insulation, and padded collar ensure comfort for workers. Steel shank adds arch support. Non-corrosive steel toe meets or exceeds ANSI Z41 PT91 M I/75 C/75 Standards. Men's sizes 7-12. Caribou II Boots are also available in wide sizes.