Rockport Women's Eberhart Blvd Boot 100% Calfskin Rubber sole Shaft measures approximately 16" from arch Heel measures approximately 3 1/4" Platform measures approximately 1/2" Boot opening measures approximately 15 1/2" around Adidas adiPRENE and adiPRENE+ footbed pads combine to create lightweight heel cushioning for maximum shock absorption and forefoot cushioning for resiliency adiPRENE is placed in the heel of Rockports footbeds. Its a mixture of EVA and rubber like material for maximum shock absorption that helps cushion upon impact adiPRENE+ lies beneath the forefoot in the footbed. Its a mixture of EVA and a special expanded plastic for rebound that helps you push off