JOYO EQ-MP3 3-Band EQ Equalizer System Acoustic Guitar Preamp EQ Equalizer Piezo Pickup LCD Tuner Amplifier: Connect with external speaker and audio inputs press to control playing from memory card or USB disk.Rotate to adjust frequency(bass middle treble) and level very convenient.1 x EQ equalizer 1 x piezo pickup rod 1 x battery box 10 x mounting screws 1 x base 1 x cable tie.3-band preamp EQ equalizer features accurate tuning backlight LCD display battery indicator light.Lightweight compact 3-band equalizer well fitted into the acoustic guitar allows easy tweaking controls for better performance. Specifications: Net Weight: 95g / 3.35oz Bass: ±12dB at 75Hz Product Dimension: 79*49*26mm / 3.11*1.92*1.02in Middle: ±12dB at 750Hz Color: Black Power Supply: 1 * 6F22 9V Battery (Not Included) Memory Card Slot: Yes Material: Plastic + Electronic Components Treble: ±12dB at 10KHz Tuning Range: 0A(27.5Hz)-8C(4186.01Hz) Package Weight: 160g / 5.64oz USB Port: Yes Package Size: 10.5*7*7cm / 4.13*2.75*2.75in A4 Frequency： 440Hz Note: Please read the user manual carefully for more information before usage. Due to or other reasons the picture and material object may slightly differ. 3 band EQ equalizer set only other accessories in the pictures are not included. Due to manual measurement there may be deviation please in kind prevail. Packing List: 1 * User Manual 1 * 3 Band EQ Equalizer 1 * Cable Tie 1 * Plastic Base 10 * Screw 1 * Pick- Rod