Triggersticks?

[Mindfield]

I got a set of joysticks 'n paddles from an auction recently, and there were included two unknown pieces of plastic that, upon arrival turned out to be a pair of Triggersticks.

 

Supposedly they're for Atari, but I can't see it. The only way I can see them fitting over the joysticks is if you were to remove the rubber boots, 'cos with the boots on the triggersticks go down about 3/4 of the way, and won't go down any further. Hell, even with a bootless joystick, they're too loose -- they rattle and there's way too much play to achieve any accuracy with them. Anyone seen these things before? They're pretty basic -- purely mechanical. The thumb trigger is attached to a post, which angles outward at the bottom underneath the base and terminates in a round "+" shaped activator that presses the CX40's fire button. But I can't figure out how these things are supposed to go on.