1. Internal DIP switches allows you to select the boost frequency and equalization settings. 2. Uses the highest available with a discrete FET design and low impedance output. 3. Use true mechanical True Bypass switching. 4. Provides up to +20dB of pure boost, and let the tone have a more stereoscopic flare of high and low frequency, and do not produce auditory fatigue. 5. mini size with blue indicator and transparent rotary knob. Internal DIP switches Input Impedance: 1M ohm Output Impedance: 1k ohm Power Supply: 9VDC or 18V (center minus plug)(adapter not included) Color: As Shown Material: Metal+Plastic Package Contents: 1 * BP Booster Guitar Effect Pedal Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.