The uppers of these Rocky S2V boots are strong leather (it's resistant to both water and flash), breathable, yet hard-wearing, Cordura (resists abrasions like no other) with well-fitting Lycra tongue. PTFE (polytetrafluoroethylene) has been applied to the footwear to provide additional flame resistance. This combination of materials allows these Berry-compliant boots to fit comfortably and be highly durable. Since heavy objects could plummet unexpectedly, or you could be walking in hazardous areas, these steel toe boots meet the ASTM Protective Toe standards as well as ASTM standards for electrical hazard. A Berry Compliant moisture wicking lining provides comfort and wicks away perspiration. Utilizing cutting-edge S2V Sieve technology, these boots disperse of water rapidly (better than the usual drain plugs), are breathable and circulate air to keep your feet feeling cool and dry. A Rocky Air-Port cushion footbed gives you a comfortable step, as the Aegis Microbe Shield helps fight bacteria, odor and fungus. You'll have steady footing and arch support due to the fiberglass shank of these S2V boots. The high-walled Vibram outsole is durable (allows it to last), is lightweight and resists abrasions. Roll-Stop Ankle Stability ensures the structure is sturdy and it helps prevent your ankles from rolling inside your boots.