Features: Mini preamplifier with impedance matching function for acoustic guitars. Supports 2-band EQ(BASS & TREBLE) and volume adjusting. 6.35mm plug for connecting musical instrument and 6.35mm output jack for connecting guitar amplifier. It can also turn your home stereo into a guitar amplifier, allowing you to experience the pleasure of music performing. ABS material and compact size, durable and lightweight, convenient to carry around. Specifications: Material: ABS Power Supply: 1 * 3V CR2032 battery(not included) Item Size: 9.5 * 4.5 * 2.5cm / 3.7 * 1.8 * 1in Item Weight: 33g / 1.2oz Package Size: 14 * 10.5 * 4cm / 5.5 * 4.1 * 1.6in Package Weight: 53g / 1.9oz Note: The guitar showed in the picture is not included. Package List: 1 * Preamplifier