Neewer Guitar Plug Amp Metal Effect Rechargeable Electric Guitar Headphone Amplifier, Portable and Compact, NW-GA-4 Metal effect electric guitar plug headphone amplifier Designed with 3 adjuster: gain, 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 headphones, portable speakers, mixer or recorder Note: Guitar and headphone are NOT included