The PSA-120S from Boss is a 500mA 9V AC adapter for BOSS Compact and Twin pedals, ME-50/-20/-20B Multi-effects, the DB-66/-88/-90 metronomes, battery-powerable DR-Series drum machines, FC-Series foot controllers, MC-202, SH-101, SP-202, TR-626, and all TU-Series tuners.

Note! Will not work with DR-Series models that cannot be battery powered, e.g. DR-770, DR-880.