Thank you for viewing. This is the silver harmonizer RCA advance, a virtual earth accessory from Audio Mijinko. There are no noticeable scratches or stains. You can use it simply by plugging it into a spare RCA terminal on your audio equipment. The Silver harmonizer series seems to be particularly popular in Audio Mijinko's product lineup, with many variations available. The RCA advance I am offering this time is the successor to the previous model, meaning it is the current model. Like its predecessor, the silver harmonizer, it is a virtual earth for standard RCA terminals, so it can be used in many situations and is a product I recommend to anyone. Thank you for your consideration!