Main: 3mm 85% Yulex® natural rubber/ 15% synthetic rubber by polymer content, lined with 95% polyester (51% recycled)/ 5% spandex inverted microgrid. Exterior: 88% recycled polyester/ 12% spandex. Natural rubber is from sources that are Forest Stewardship Council® certified by the Rainforest Alliance. Fair Trade Certified™ sewn.