This is Mine Den's Filter Plus, also used in the Tokyo Dome. I've been using it for six months, but I'm selling it because I bought a higher-end model. It can powerfully enhance the filtering effect of a power distributor with a noise filter. This product was created to improve the power environment widely and inexpensively. When plugged into an empty outlet of a power strip or distributor, the sound changes over a few seconds, improving the soundstage and increasing the resolution. The low-frequency contours become clearer, and reverb becomes easier to hear. Supported voltage: ~AC120V Tested with distributor: TASCAM AV-P250