Description of Eva Sole.. Why we Select.. this One.. More Flexibility. EVA tends to be softer than rubber, which means it means we have more flexibility Lighter. The EVA is lighter than rubber which, combined with the merino wool uppers, makes for a much lighter shoe. Keeps you Warmer. EVA doesn?t conduct as much heat, which means your feet will stay warmer for longer. This makes it the ideal sole for our wool boot. Shock Absorption. Our EVA soles absorb more of the step impact making for a more comfortable walk or run in our shoes. Durability. EVA soles can last longer than other soles.