KEEN mid-soles will be made up of EVA or PU materials. Both provide excellent comfort, but there are key differences between the two.
PU is an organic polymer known for its resilience and compression resistance. It is slightly heavier with a higher density, but in footwear it excels when it comes to durability. PU will provide you with the "millionth step comfort".
EVA (Ethylene-vinyl acetate)
EVA is a synthetic polymer known for its superior cushioning. It is a lightweight polymer, which still maintains excellent shock absorption. Due to its lower density structure, EVA can compress over time, which means it will start providing less support after significant wear. EVA will provide you with a superior lightweight cushioning.