Men's Muck Chore Cool Waterproof Rubber Boots 664911-CSCT-000 Muck's best-selling Chore Muck Boot now has Xpress-Cool technology which is an exclusive moisture lining that keeps your feet both dry and cool. Find out for yourself how we are giving Sweaty feet the boot! Features -Sockliner lining to reduce friction and heat build up -Steel shank for additional arch support -Upper is triple reinforced in the toe area and quadruple reinforced in the heel area -4mm NEOPRENE bootie with four-way stretch nylon,100% waterproof, light-weight and flexible -ASTM F2413-11 MI/75 C/75 EH -Shaft Circumference: 17in Men's Muck Chore Cool Waterproof Rubber Boots