PE special tool

[rjmorel]

Can anyone tell me how the 12mm wrench stays on in this pic? It looks like the rubber band needs to go up onto the flanged pin which in turn would pull both wrenches down into the top mounting bracket. As it is now looks like the 12mm wrench will just fall off. Asking cause I've never had one or seen one in person and saw this pic on inet. I want to make one but am wondering how they go together and stay on. thanks

[mazz]

This will explain how it attaches together.
pics credit to Tim Coates on PE forum FB

[ESR80PE]

There a spring loaded ball bearing in the part where the 12mm part clips over.