EH-2 Enhancer The ads used to say that the EH-2 adds brilliance, dynamics and presence to your sound. What it does is to dynamically modify the high-frequency harmonics. This restores the clarity and delicate harmonic structures lost through signal processing with multiple effect units. It is well suited to studio work where it can have a huge impact on the clarity of the recorded sound. The MIX control can be adjusted from INV (Inverse) to NOR (Normal). Thos control will cut or boost the signal. The FREQ (Frequency) knob controls what frequencies are affected by adjusting the cut-off frequency in a filter. The setting of the SENS (Sensitivity) knob will determine how much of the chosen frequency band that will be affected. SpecificationsControls: Mix, Freq, SensConnectors: Input, Output, AC AdaptorCurrent Draw: 24 mA (DC 9V)Recommended AC Adaptor: PSA SeriesGood working condition. These were only made for a short time in the 90's. They are highly collectible.WORLDWIDE AND EXPRESS SHIPPING AVAILABLE!International Buyers: Standard shipping has NO TRACKING but a customs number. I recommend buying insurance $. Express Shipping takes 5 days or so. It comes with a tracking number.Buyer is responsible for import taxes, customs fees, etc.