COMPOSITE TOE: Left and right asymmetrical, non-metallic carbon-fiber toes, a composite material, offer an unobtrusive fit and are 15% lighter than steel; The Portland 6" Waterproof work boot meets or exceeds ASTM F2412 and F2413 I/75 and C/75 Standards TRACTION: Oil- and slip-resistant, non-marking, rubber outsoles are used for improved traction that meet or exceed ASTM F1677 MARK II and ASTM F2913 SATRA Non-Slip Testing Standards; Lug sole patterns provide grip even on slick surfaces WATERPROOF: KEEN. DRY is a waterproof, breathable membrane liner that lets vapor out without letting water in to keep your feet dry and comfortable; The Portland 6” work boot does have a mesh liner that integrates with the waterproof membrane UNDERFOOT PROTECTION: Made with a TPU Shank, used for midfoot support, and torsion stability; Featuring a Heat resistant, rubber outsole rated up to 572° F / 300° C and a 90° heel (5/8” height) that helps secure the foot on ladders SAFETY & COMFORT: KEEN. BELLOWS FLEX technology allows footwear to bend and flex 3x easier; KEEN Luftcell air-infused, PU midsoles are used for weightless comfort; CLEANSPORT NXT provides natural odor protection using probiotics