Even the best parties have to end sometime, but your JBL PartyBox Stage 320 can keep the vibe going twice as long with this JBL Battery 400. When your rechargeable battery is running out of juice, it takes just seconds to pop a fresh battery into the slot on the back panel. Double the great times, and enjoy the peace of mind that comes with an official JBL battery. It also can replace the rechargeable battery inside a JBL Xtreme 4 wireless Bluetooth™speaker when it starts to degrade. Each battery comes in FSC-certified packaging printed with soy ink.