Our warmest surf booties for the most extreme cold, the R5® Yulex® Round Toe Booties feature 7mm 85% Yulex® natural rubber/15% synthetic rubber by polymer content; 100% external seam sealing; a fast-drying inverted microgrid interior lining; and a durable, textured sole for grip. Made in a Fair Trade Certified™ facility. Suggested water temperatures: 32–38° F/0–3° C.