Cell Drive 4 GB Back-Up Power, USB 2.0 Charge, Data Sync and Mass Storage Drive for Mobile/Smart Phones, PC, and Mac - Black Rechargeable Backup Battery: Fully charged Cell Drive allows for over 1 hour continuous talk time USB Charger: Fully charges mobile/smart phone and any USB device with a standard 3.5 mm adapter Data Sync & Media Transfer: Cell Drive serves as a data cable to sync and transfer media between phone and computer using the phone provider's or third party sync software Data and Media storage: Cell Drive provides 4GB or 8GB internal flash memory to store data and media Cell Drive multi-function device helps eliminate accessory clutter and is essential for the business road warrior and is ideal for the office, home and school