INV 2407 9-Volt Battery Included The MXR M133 Micro Amp is a versatile gain/boost pedal designed for guitarists. Here are the key features: Boost Your Signal: The Micro Amp lets you take control of your volume level before your signal goes to the amp. Use it to boost your signal for leads or match output levels between different guitars (like humbuckers and single-coils). Simple Operation: It has a single Gain knob that adjusts the total output volume when engaged. The footswitch toggles the amp on/off, and a red LED indicates when it’s active. Power Options: You can power it with a single 9-volt battery or use the Dunlop ECB-003 AC adapter (sold separately). Compact and Durable: The Micro Amp comes in a tough, compact metal enclosure, making it a reliable addition to your pedalboard. Whether you’re pushing your tube amp into that sweet spot or compensating for signal loss in a pedal chain, the MXR Micro Amp has you covered! 🎸