Coin Mech tester??

[Justin W]

Picked these up for $10.  Is this specifically to test coin mechs or can it test the vending mech in the machine as well?  Which type of coin mechs can it be used on?
The only reference Ive found is here: http://mr-barber.com/smc/National_Rejectors_Electric_3400.pdf   Looks like Im just missing a couple of leads which are easy enough to make I'd imagine.

Anyone have any other reference material on this or its use?

[Yarochrehc]

Almost bought those, but don't know a thing about them

[Pat Pixley]

I have one  there great and I paid $40 for mine