I can answer my own question!
I finally got some joy by using Google's "search by image" feature, and here's the same electromagnet, with better description (well, sort of!)
The tail of these Super Miniature Solenoid Electromagnetic Brake is a piece of strong magnetic(NvFeB), when NOT energized, it can suck inner metal core, the force is stonger.When energized (one wire is connected to the positive electrode, another wire is connected to the negative electrode), magnetic is weaken, the inneer metal core can move freely. Thus, its function is equivalent to a mini electromagnetic brake: power-release,and no power-brake.
1 when the wire A is connected to the positive pole,wire B is connected to negative electrode, the magnetic is weaken .
2 In opposite,when B wire is connected to the positive pole, wire A is connected to negative electrode, the magnetic is enhanced.
The electromagnet is a bit special ，There is a strong magnet In the end ，if no electricity the magnet will absorbing the shaft , After electrify offset the magnet magnetic , then the Shaft can be activity
In other words, I probably CAN use these, but it's going to require some rubber bands and a bit of annoyance.
I guess the sequence would be:
Find rubber band of right strength.
Ping a positive voltage through the solenoid to get it to release.
Immediately ping a negative voltage through it to suck the core back in, then release the current hoping that the built in sticky magnetism will hold it.
Not really ideal - but hope this helps someone!
Ideally, what I was after was some solenoids of around the same price and size, but that would have a spring and "push" out briefly, to tap against a glass or tuned piece of metal.