"Oytex™ rubber is FSC™ certified and contains biobased carbon from recycled oyster shells, sugar cane, plant oil and renewable rubber. The polyester fabric laminate on both sides is 100% rPET. Oytex™ is an eco-friendly replacement for neoprene. With the same dual-sided imprint capabilities as our Duplex line, with all the stretch and insulating properties, it's a more sustainable alternative to traditional neoprene. Pretty cool, right? Stay hydrated and hands-free with our Hydration Sling! Easily carry a 32oz water bottle anywhere you need to go. Water bottle not included."