Bose S1 Pro+ System Battery Pack

Up to 11 hours of play time when used at high-output levels for performance use you can count on

Lithium-ion battery technology provides high energy density and full-output use of your S1 Pro+ system without compromising volume level. 

Dual charge modes allow the S1 Battery Pack to be trickle-charged while the S1 Pro+ system is in use with AC power, or when not being used for play, the switchable Quick Charge mode can be used for rapid charging
Permanently install the battery inside the S1 Pro + system for safe and easy charging.