Finally, a rubber bit that is not too thick! Rubber bits are made of high quality polyurethane. Please make sure only to use rubber bits on horses producing ample saliva. Rubber is a soft material and is subject to natural wear in the horse's mouth. Wear can be increased if the bit is fastened too high up in the horse's mouth and the horse manages to chew the bit with its back teeth. Please ensure the correct positioning of the bit before use.