The Boss PSA-230 power adaptor is designed to power all the current range of Boss FX.
Having bought one to power my latest aquisition, the Boss ME-20 multi FX, it definitely does what it says on the box. It has a very useful green indicator light on it too, so you can see when it's on !
Call me old fashioned, but my only gripe with this, and indeed all modern PSUs, is that the mains cable looks rather flimsy. But I guess that's how they make 'em these days !