Duet is a very beautiful and interesting machine. There are three ways to win, and the player must select before playing, or put in another nickel to load the full ruleset of the game.
Completing the sequence of 1-10 will award 20 replays, with the possibility of earning a 'reserve' set of replays - up to 200!
http://ipdb.org/showpic.pl?id=3065&picno=64416&zoom=1