Mugen Power Blackberry Z10 (4 LTE) Double Juice 3800mAh Extended Non-Slip Better Hand Grip With Back Cover Mugen Power Extended Battery 3800mAh "Over 2X Longer Runtime (Original Battery Capacity: 1800mAh) *Not compatible with Z10 3G Version* Unique narrow curve cover design to better hand grip avoid Actual Runtime Testing: Continuous Playing YouTube video - Mugen Power: 12hrs, Original: 5hrs - With Wi-Fi on, Medium brightness, Medium Volume 24 Months Warranty