Anti-Fatigue Technology: A comfort system designed with shock-absorbing, geometrical technology that returns energy back to the foot to deliver all-day support and comfort. HoverSpring: Our proprietary lightweight HoverSpring foam provides industry leading underfoot comfort and flexibility while being durable enough for the harshest environments. Timberland PRO Rubber: Heat-resistant, durable rubber compound offers enhanced slip, oil and abrasion resistance. Metal Free: This footwear is metal-free and won't set off metal detectors. ReBOTL Material: Products with ReBOTL material contain at least 50% recycled PET (recycled polyethylene terephthalate, the stuff plastic bottles are made of) excepting trace materials.