One of the most common Hamilton Electrics, it 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.

Hamilton Skip Jack with most common style of dial and hands; 505; 1961

HHamilton Skip Jack with RR style dial and hands; 505; 1961

HHamilton Skip Jack with RR style dial and hands; 505; 1961

HHamilton Skip Jack with RR style dial and hands; 505; 1961