KEEN UNEEK O2 UNEEK O2, which I color-directed myself. I'm selling these because I have some in stock. Open Air Sneaker UNEEK. O2 is the molecular formula for oxygen, a closed-heel, lightweight version. By incorporating O2 foam, we've succeeded in reducing the weight by 25%, realizing a feeling of being wrapped in air. I will not accept any price negotiations. Thank you for your understanding.