3250mAh Li-ion battery, the original, extending your Big Jambox speakers runtime for more music, less charging! ^^ Designed specifically for Jawbone Big Jambox Bluetooth Speaker (Model J2011-03-US), ensuring seamless compatibility and optimal performance. ^^ Features built-in voltage detection & delay circuits to prevent overcharging, overheating, and ensure stable power output. ^^ Simple plug-and-play replacementjust remove the old battery and install the new one in minutes! No tools or expertise required. ^^ High-quality Li-ion cells deliver consistent power, longer lifespan, and reliable performance, bringing your Jambox speaker back to life!