An key feature of the R6003 Work Boot is its Rocky Waterproof construction. It combines a waterproof inner layer with the upper providing a barrier that helps keep water out and feet dry. A key comfort feature of the R6003 is its contoured removable polyurethane cushion insole providing direct underfoot cushion comfort. The polyurethane material used in its insole is known for its cushioning while not bottoming out features. Some open celled foams feel very comfortable to the initial touch, but will tend to break down faster than a product made with polyurethane. Plus, it is extra thick in the heel contact area. This provides additional underfoot comfort to the wearer. In addition to meeting the highest Astm F2413 Impact and Compression standards, Rocky stock # R6003 also complies with its Electrical Hazard standards.