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