Chung Shi DUX - Unisex Comfort Clogs with Arch Support. Time to balance! The DUX Clog beats the competition with great arch support and heel comfort. We call it our "heel pain" shoe. It is thermo-reactive so it conforms itself to your foot shape while wearing. And, it is laboratory verified as not containing toxic chemicals like other brands. The ergonomically designed shoe is made from high quality, super soft Duflex material. Duflex X-terrain is a breathable, non-aging cell construction rubber with thermo-reactive properties.