A friend has a Hang Glider machine and we always wondered why Bally put the "100 when lit" bumper caps on pop bumpers that are always lit. Its sister machine, Hi-Deal, has the correct "100" bumper caps, but these are red in color.

We came to our own conclusion that Bally had an excess of "100 when lit" bumper caps and they didn't want to spend the money to make blue "100" bumper caps. They installed those incorrect bumper caps and, back in the day, very few players probably noticed the bumper cap error.

It would be simple to just switch out the bumper caps to the "100" style bumper caps. Unfortunately, I don't think they make Bally style blue "100" bumper caps. You can always get the red "100" bumper caps and paint them blue!