Bellow akara ụwa valvụ, ndị dị oké mkpa akụkụ nke nke-metal n'okpuru, akpaka mpịakọta ịgbado ọkụ ala nke bellow na azuokokoosisi akụrụngwa, akpaka mpịakọta ịgbado ọkụ n'elu bellow na ejikọta efere, nke bụ metal mgbochi betweeen ọmụmụ na ikuku, hụ esiwe na efu-ehi ehi.
