Wonderful Waldhausen bit. Waldhausen's new rubber bits are made of high quality polyurethane. Please make sure that rubber bits are only used for horses that produce ample amounts of saliva to avoid any rubs on the gums. Rubber can be a fantastic starter bit for young horses. But rubber is a soft material and is subject to natural wear from the horse's mouth. If the bit is fastened too high it can be chewed by the back teeth, reducing the longevity of your bit. Don't use rubber bits if they degrade.