Oliver Men's 14'' Leather Lace-up Mining Boots Leather, TPU, PU, Rubber Dual Density PU, Rubber Soling Technology - combines a soft shock-absorbing low-density PU midsole with a high density hard wearing rubber outsole, the long-wearing all-terrain rubber outsole is designed for superior grip and durability Heat-resistant - sole resists temperatures up to 572 Fahrenheit Chemical-resistant - sole resists mineral oils, acids, alkalies, animal fats and oils Excellent slip resistance - on uneven terrain or slick surfaces Electrical hazard - rated outsole meets ASTM F2413-11 M I/75 C/75 MT/75 PR SD