Experience ultimate warmth in extreme cold conditions with Patagonia's R5 Yulex® Regulator® 7mm Round Toe Boots. Made from 85% natural rubber and 15% synthetic rubber, with external seam sealing and Fair Trade Certified™ factory production, these boots keep you comfortable in 32°–38° F/0°–3° C water. Patagonia's warmest booties for the most extreme cold conditions.