ALCLAP Google Pixel XL Battery Case-5200mAh Extended Battery Fast Charger Protective Case Power Pack Juice Bank-Charging Battery Pack High Battery Capacity: 4200mAh capacity for extended use and can fully charge Samsung Galaxy S7 1.2times, built-in Lithium-polymer battery can continue to provide about 12hours video watching , 8hours surfing internet,30hours music playtime,which based on experiment testing data.