ITEM NAME:Active Endpin Jack Preamp Piezo Pickup Mounting Base Kit For Acoustic Guita B4J3 Active Endpin Jack Preamp Piezo Pickup Mounting Base Kit For Acoustic Guita B4J3 Need a 9 volt battery power supply size:10.2*13mm note:After complete the installation, almost can not find it, hidden inside the guitar body, small volume, do my utmost to avoid affect the vibration of the guitar, it did it! Perfect! In order to ensure transportation safety inside the package does not include the battery :) The output of the powerful Have the volume and tone control color:Black Material: Metal Installation: 1. Remove the tail button, Drill a hole diameter of 12 mm, From inside the guitar body wear out a piece of rope, Use the rope drag The body of the pick-up, Then with a nut fixed it 2. Drill 3 mm holes in the side hole of the saddle. Through the piezoelectric strip 3. volume control of torsion, Paste on the edge of the sound hole inside Package listing: 1 x Pickup 1 x Mounting base 1 x Bag 1 x Cable tie 1 x pickup stick Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.