Sound quality improvement speaker for Game Boy. - Brand: SUNSOFT - Product Name: SOUND BOY - Type: Speaker - Application: For Game Boy only - Function: Improves sound quality Box and instruction manual included. There is yellowing due to aging. The terminal part seems to be clean without any liquid leakage. Power turned on. Sound is also fine. This is just a casual observation, so please refrain from purchasing if you are concerned. Thank you for viewing.