Slim vs. Fatboy

The fatboy was made 1958-61 while the slim was made 1961-68. Here are my two Gillette adjustables. My Fatboy is an F2 from 1960, and my Slim is an H1 from 1962.

F2 Fatboy (195): 2.8 oz., 3.45 in.

H1 Slim: 2.5 oz., 3.56 in.

The heads of the slim and fatboy are almost identical. However, the head on the fatboy is more domed shape than that of the slim. The fatboy's handle is a little shorter and "fatter." The fatboy is a little heftier in the hand. They both provide an excellent shave. 

An interesting difference: the numbers on the slim line up with the knurl on the dial
while the numbers on the fatboy line up on the flats of the dial.