nylon Made in USA Made exclusively for Outdoor Country LLC Made taller for the people with long shins To Determine if you need an Extra Tall Snakeguardz, please measure the length of shin from knee to bend on top of foot. The XTall measures 14" from knee to bend at ankle on all sizes. The rest of the Snakeguardz will cover a part of the foot depending on your foot size. (shoes do not come with product, heavy leather boots need to be worn with snakeguardz) Then Measure AROUND the largest point of your calf to determine correct size to order: Large - 14-18 inch calf, X-Large - 18-23 inch calf, XX-Large - 21-24 inch calf, XXX-Large - 24-27 inch calf.