This is a BOSS CS-3 Compression Sustainer. I was able to confirm that it powers on, but the overall condition is poor, with noise and difficulty in determining whether there is a change in sound quality. Each knob seems to be functioning. The check lamp lights up, but the LED is dim. When I received it, the bottom cover was missing and held on with tape. I think it needs to be modified by someone with knowledge or overhauled for normal use. Thank you. Type: Electric Guitar Manufacturer: BOSS