Igniter AN-M9 consists essentially of two concentric steel tubes joined at both ends to form an annular space which is filled with white phosphorous (WP) for land bombing or sodium (Na) for water bombing. The sodium filled igniter was formerly called Igniter E2. The inner tube, which is approximately 1.25 inches shorter than the outer tube, contains a small coil spring for snubbing inserted burster M13.
WP or Na, 1.6 lbs
TM 9-1325-200, Bombs and Bomb Components (1966)
OP 2216, Volume 1 - Aircraft Bombs, Fuzes, and Associated Components (1960)