In a "fixed-key" balafon, the keys are suspended by leather straps just above a wooden frame, under which are hung graduated-size calabash gourd resonators. A small hole in each gourd is covered with a membrane traditionally of thin spider's-egg sac filaments (nowadays more usually of cigarette paper or thin plastic film) to produce the characteristic nasal-buzz timbre of the instrument, which is usually played with two gum-rubber-wound mallets while seated on a low stool (or while standing using a shoulder or waist sling hooked to its frame).