OluKai Kumu Womens Leather Flip Flops with Arch Support Kumu koomoo Translation Good Looking. The OluKai Kumi is a timeless full grain leather sandal with a stylish twist. This is a really comfortable Flip Flop sandal with added arch support great for Women who want to avoid arch or heel pain. Upper is constructed Antiqued or metallic full grain leather straps with pigskin lining and neoprene backer. Footbed is constructed of an Anatomical compressionmolded EVA midsole with full grain leather footbed. Outsole is constructed of Nonmarking gum rubber outsole with traction pods.