DOUBLE X1 Guitar Pick-up Acoustic Guitar Preamp Professional Preamplifier Soundhole Pickup Magnetic Pickup Single Channel with Volumes Adjustable Reverb Function for 96-104mm Sound-hole It is single-channel magnetic-pickup system that features a soundhole mounted preamp with rotary controls for and tone. DOUBLE X1 Guitar Pick-up Acoustic Guitar Preamp Professional Preamplifier Soundhole Pickup Magnetic Pickup Single Channel with Volumes Adjustable Reverb Function for 96-104mm Sound-hole: Using high-purity self-adhesive copper wire combined with RX winding technology it brings lower noise sound.The exclusive design patent of the rotating battery compartment does not require additional battery packs or battery boxes and the battery can be quickly and easily replaced without loosening the guitar strings which is simple and convenient.Simple and novel more ergonomic design brings more user-friendly control-method and more convenient installation experience suitable for install in 96-104mm in diameter of acoustic guitar soundhole.The coil is no longer expose the sound column and the sound is thicker and more grainy.Volume and tone adjustable design suitable for various performance situations.The cork clip interface makes the installation more convenient and there is no need to worry about the clip opening being too loose and slipping off anymore. Specifications: Item Weight: 147g / 5.19oz Power Supply: 2 * CR2032 battery 3V 220mAh Package Weight: 315g / 11.13oz Package Size: 18 * 12 * 6.5cm / 7.09 * 4.72 * 2.56in Material: ABS Suitable for: 96-104mm soundhole Item Size: 149 * 60 * 33mm / 5.87 * 2.36 * 1.30in Package List: 1 * Screwdriver 1 * Tail-pin Leather Sheath 2 * Gasket 1 * Manual (English) 2 * Cable Cleat 1 * Guitar Pick- 1 * Output Tail-pin