The Patagonia Yulex Regulator Lite 1.5mm Vest is a stretchy, neoprene-free 1.5mm vest made of 85% Yulex® natural rubber/15% synthetic rubber by polymer content; the natural rubber is from sources that are Forest Stewardship Council® certified by Preferred by Nature™. Best for water 65°–75° F/18°–23° C. Made in a Fair Trade Certified™ factory.