First generation Pos-I-Tron used a solid wire, not a cable, special housing. The Nishiki Junior Sport 24" wheels came with it first in the Nishiki line. The front freewheels are a wee bit fragile, most had hefty guards on the rear mechanism to protect it in case of a fall.

At the time it was rumored that Shimano was prototyping a Dura-Ace version providing the advantage of shifting while coasting through a corner to be able to resume in the perfect gear, too much drive train friction to make that possible advantage worthwhile.