Nowadays, skins for scarfs or other percussion instruments are no longer made of animal skin, but of plastic. The skins are mounted and tensioned on the boilers by means of a clamping ring and clamping screws. Depending on the tension force, the tone becomes higher or lower (together with the diameter of the boiler). There are single or multi-layered heads, whereby the resonance heads on the underside of the bowls are usually thinner on the striking heads, which are pulled up on the upper side.