Birkenstock Men's Kairo Birko Flor Sandals Birko-Flor Classic thong styling with cork contoured footbed, fully adjustable strap, and shock absorbing EVA sole. High quality materials and unique construction give durable comfort and long lasting good looks. Your feet benefit from free movement, constant exercise and improved circulation, resulting in long lasting comfort and better health. Fully Adjustable Buckle At Ankle Strap. Fully resoleable and renewable!