Premier CNCIP4 Clip N Charge Battery Holster for Apple iPhone 4 Talk Time: extends your iPhone talk time up to an additional 9 hours. Standby Time: extends your iPhone standby time up to 20 additional days. On/Off Button: allows you to activate charging mode when needed. LED: holster battery power/charging indicator. 10 minutes standby: when phone is taken out of holster during charging mode the holster will stay on for 10 minutes (if phone is docked within 10 minutes it will continue charging).