The VOX Cooltron Snake Charmer Compressor is a versatile compressor designed to enhance sound quality. Operation has been confirmed with both a DC adapter and batteries. Due to its age, there are some scratches and stains. This is a listing for the main unit only. Please consider this before purchasing. - Brand: VOX - Model Name: Cooltron Snake Charmer Compressor - Function: Compressor - Adjustment Knobs: Volume, Reduction, Emphasis, Release, Attack, Compression - Input/Output Terminals: Input, Output - Power: DC 9V Thank you for viewing.