The Swing is anatomically correct so that when you walk it doesnt make the normal flip-flop noise that you normally get with other sandals. The footbed is made from naturally soft & comfortable Nubuk leather with a dual density EVA foam midsole to absorb shock & provide comfort. The strap is a soft slightly stretchy fabric that hugs your arch & stops the Swing sliding off. Grip & control is provided by the Fri Xion XF sole unit, made using the same sticky climbing shoe rubber with a studded pattern, it is super grippy! A brilliant example of a simple product!