The darbuka, dumbek and other similar shaped drums are common percussion instruments found in many diferent cultures in a variety of forms. The darbuka's body can be wooden, metal, ceramic or of any material that can be formed into the appropriate shape. Some cultures, however, prefer the sounds from specific materials. The skin can be plastic, natural skin (goat, sheep, fish). The body in Turkey and Balkan countries can be metal/ceramic with both plastic and natural skins. In Iran and Africa, ceramic ones with natural skins are prefered. The difference is the sound that you can hear out of each type. The metal ones have a sharp sound. Whereas the ceramic ones have a bass sound. If you know the size (radius) of your metal darbuka, there is a big chance that you can find a ready plastic head from a music store. However, it is not easy to find ready-made natural skins since the ceramic ones are hand made and they can have different head sizes.