Stainless steel with a single jointed mouth. The bridle pieces are attached through the eye at the top of the bit to apply more pole action. the slotted cheeks allow for the rider to alter the rein position to increase or reduce the curb action.
This is the best sandle ever made and I loved them so much I bought a spare pair as I can't buy them any more. So disappointed that they're discontinued, a fantastic, comfortable shoe.