Didgeridoos can also be made from PVC pipes, non-native hard woods (which are split, hollowed and rejoined), fiberglass, metal, agave, clay, hemp (a bioplastic named zelfo), and even carbon fiber. These didgeridoos usually have an upper inside diameter of around 1.25" down to a bell end of anywhere between two to eight inches and have a length made to the needed key. The mouthpiece can be made of beeswax, hardwood or simply sanded and sized by the craftsman. In PVC, rubber stopper with a hole cut into it can be used.