One of the most common Hamilton Electrics, the Hamilton Skip Jack was released in 1961 with the 505 movement.

With the first dial style (photo #1 below), it is very similar to the Nautilus 501: the dial is almost identical apart from the colour of the markers and the case only differs in the design of the lugs; they are much finer on the Skip Jack.

The other three photos show the Skip Jack with the Railroad style dial and hands.