Snug Fit design boots: Slip-on boots that feel like they are laced on; superior ankle/heel support to reduce incidences of ankle roll-over; superior arch support to reduce fatigue, finally a gum boot that moves with you, as part of you. Heavy-duty rubber pull straps. Ultra flexible: Exceeds 305,000 Flex Rating. Compatible with ice studs. Shaft measures approximately 13.75" from arch, Heel measures approximately 1.25", Platform measures approximately 0.75", Boot opening measures approximately 17.75" around. NFPA : 1971 - 2013 protective footwear for structural fire fighting, CSA Z195-14 / ASTM F2413-11 Grade 1 Steel toe and plate, CSA Omega - Electric shock resistant 18kV