Its a pedal power supply.
Its one of those thing that player bought from a guitar shop abroad.If my x student hadn't showed me I wouldn't know such thing exist.I bet there's more stuff in Japan that we don't know about.Haha..
At first sight and touch its an interesting device.Its no more bigger than my cigarette box.Housed in a metal enclosure.The size is excellent for tight spot.the weight wouldn't burden your velcro for an odd angle fitting.An adapter and power patch are included of course.
As for the juice,its 50% more than my comfortable 200mA rating.300mA should be alright.Looking in it revealed 2 easily available Regulator IC that's quiet cheap to replace should the need arise.The PCB are well arrange,symmetrical and components are fairly distance from one another.I like it.
Thumbs up Crews Maniac Sound.