US Bomb, 500 lb Fire, BLU-23/B
The BLU-23/B, 500 pound fire bomb is a smaller version of the BLU-1/B. In addition, it has an initiator adapter added which is designed to prevent napalm from leaking into the initiator well. Otherwise, the bombs are identical and are assembled and stored in the same manner.
Collaborative Ordnance Data Repository