This is the Profoto Li-ion Battery 4S2P. It is compatible with the Profoto Pro-B3 750 Ws battery-powered flash and has a capacity of 80.4 Wh. Providing enough power for up to up to 250 full power flashes and up to 60 minutes of full continuous light. It can be charged with the Profoto Battery Charger 5A (100445) which is not included.