This American designed bomb was particularly suitable against ammunition dumps, railway engines and cars, airplanes on the ground, all types of construction and light surface vessels. The bombs were usually filled with TNT or Amatol but the AN-M64A1 bomb was filled with TNT or Composition B. The total weight of the heavier Composition B filled bomb was 535 lbs of which 274 lbs was the explosive. The charge / weight ratio therefore being 51%. TNT filled bombs had a charge weight of 267 lbs with the Amatol charge being 262 lbs.
The overall length of the bomb including the tail was 57 inches with a diameter of 14 inches. The thickness of the steel bomb casing was 0.3 inches which was either a forging, seamless steel tubing or welded.
There were two suspension lugs on one side of the body with one lug on the opposite side.
The bomb was painted olive drab and had a 1 inch wide yellow band around the nose and rear of the body with a 1/4 inch yellow band around the body at the centre of gravity.
The tail unit consisted of four fins welded or riveted to the fin sleeve, which was secured to the body with a fin lock nut, and having four box type struts