The arctic sport ii ankle is crafted from muck's traditional hand laid rubber. To reduce weight and increase flexibility, we utilized our muckskin technology. This technology features a printed rubber coating over neoprene that is 100% waterproof. 5mm neoprene bootie for comfort and performance. Cool weather lining: soft, insulation, light-weight, performance materials for warmth and comfort. Muckskin flexible neoprene with abrasion resistant rubber coating combined with hand laid rubber for durability. Lightweight eva midsole for all day comfort and support. Rugged rubber outsole for traction. Biodewix dry footbed insert topcover with nzym for odor control and moisture management