68-72 has 2 red and 2 blue levers, they are metal with molded color ends and are held in with pins.

73 has 2 red and 1 blue levers, same as 72 back but are held in with spring clips. These clips will work on 72 and back instead of the pins but you will 2 73's to get 4 spring clips.

74-79 has 2 red and 1 blue levers but they are all plastic and push on- pull off.