The JBL Battery 600 is a portable power solution designed to keep compatible JBL PartyBox speakers, such as the PartyBox Stage on the Go, running during longer events. It features a lithium-ion battery with a capacity of 99.02Wh (21.6V/4584mAh), allowing you to extend your music playback without needing a wall outlet. This unit is quite versatile, as it includes a USB-C port that supports both charging and output. You can charge the battery itself using a PD 60W power source in about 4 hours, or use it as a power bank to charge other devices with a maximum output power of 45W. Its compact black housing measures 103 x 43.6 x 137 mm and weighs 690 g, making it easy to slip into a bag alongside your speaker. The package comes with the battery and a dedicated charging case, though you will need to provide your own USB cable.