OluKai Kumu in Coal/Kona at Robert Frost Fine Footwear and frostshoes.com has premium full-grain leather straps with soft pigskin and neoprene strap lining. OluKai Kumu has a soft and flexible nylon webbing toe post. OluKai Kumu has a premium full-grain leather or nubuck footbed cover. OluKai Kumu's EVA midsole is anatomically molded and the outsole is a non-marking, durable rubber. OluKai Kumu in Coal/Kona is available at Robert Frost Fine Footwear and frostshoes.com.