Z.VEX Channel 2 D151 Channel 2 Boost and Buffer Micro Pedal has two knobs, one controlling Master Volume and the other controlling Gain, which sweeps from unity to +24dB. Connect a music equipment power supply of 9VDC, center negative, to the power jack for use. There is no battery in your Channel 2. The Gain control adjusts both the gain and DC bias on the MOSFET transistor at the same time, causing a rushing noise when adjusted. This is normal. At low gains, your Channel 2 has an input impedance of 5 Million ohms, giving your guitar a very sparkly texture when plugging directly in, with no other pedals or tuner between. This will clear up even the longest, dullest-sounding guitar cord. With the Master turned up, the Channel 2 is exactly the same as our famous Super Hard-On pedal! With the Master Volume turned down, the Gain can be used to create clear, natural sounding distortion. Or, if you prefer to overdrive your favorite amp, leave the Master up and let 'er rip! Your Channel 2 has a 1 year warranty. The Channel 2 draws less than 10mA.