Ihe nkedo akara, nke a makwaara dị ka skru nke onwe ma ọ bụ ihe nkpuchi, bụ ihe ndị pụrụ iche nke ịghasa emebere iji nye akara mkpuchi na-enweghị nchekwa na ngwa ụlọ ọrụ dị iche iche. Ihe skru ndị a nwere atụmatụ pụrụ iche nke na-etinye ihe nkpuchi, na-abụkarị mgbanaka O-mgbanaka ma ọ bụ washer na-agbanwe agbanwe, nke etinyere n'ime nhazi nke ịghasa. Mgbe etinyere skru akara n'ime ebe, ihe nkpuchi ahụ na-emepụta akara siri ike n'etiti ịghasa na elu mating, na-egbochi ịgafe mmiri, gas, ma ọ bụ mmetọ.