I bought this adapter for my Boss SE-50 since I did not want to spend $40+ on a giant brick known as the BRB-120. I had one of the original Roland power supplies back in the day and hated how much space it took up just for a half-1U rackmount. However the plug on the AC/AC adapter I bought here is 2.1mm x 5.5mm so I also got a converter on this website to adapt it to the 3.0mm x 6.3mm plug in the back of the SE-50. I have confirmed this to be operational, and a less expensive shoehorn for the BRB-120.