This is a design for a 4,000-pound G.P. bomb of the same general construction as others in this class.
Suspension: Standard lugs 30 inches apart.
Filling: Tritonal or TNT with a larger booster, the T21, which is like the M115 except for its increased size.
Adapter Booster, M115, M115A1
Collaborative Ordnance Data Repository
OP 1664, Volume 2 - US Explosive Ordnance (1947)