the BATFE has granted permission to import the AF-2011 into the U.S., but I believe it's a modified version with two, independent triggers.
I looked into this a bit, at the time. There were two versions, one, for sale outside the US had a single trigger that fired both actions. The US version had two triggers, side by side, that LOOKED like one trigger with "two halves". ONE pull could fire both, it was two triggers (mechanically independent) being pulled at one time, which satisfied the US legal requirement.
Same mechanical process as firing both barrels of a double trigger shotgun at the same time, (pulling two triggers), the difference was both pistol triggers were "co-located" so both could be pulled with one finger.
If I remember right, it was also possible to fire only one, but this was very awkward to do.
Never saw a 3 barrel revolver, before. Have seen (in books) examples of two barrel ones, all old late 1800s stuff, save one, that was modern, a prototype that never went into production as far as I know.
Two barrels, one at the normal top of the frame, the other at the bottom. One was .357 Mag and the other was .22LR, with the firing mechanism switchable from one to the other. They did NOT fire at the same time.
I have long forgotten the name, sorry...