Neewer&reg; Guitar Plug Amp Rechargeable Electric Guitar Headphone Amplifier, Portable and Compact, NW-GA-1 Acoustic electric guitar plug headphone amplifier Designed with 3 adjuster: blend, tone, vol. Powered by built-in rechargeable lithium battery 6.35mm/0.25in plug, just plug into guitar jack, no need of installation Specially designed phone jack which lets you play along with headphone, portable speaker, mixer or recorder Note: Guitar and headphone are NOT included