Picture Keeper Stocking Stuffer - 4GB Starter Automatic Backup Device for Backing up your Photos on your PC or MAC Computer (4-Pack) SPECIAL HOLIDAY EDITION - Holiday gift themed Picture Keeper package AUTOMATIC ONE-CLICK BACKUP - Picture Keeper software finds & backs up your pictures USE ON MULTIPLE COMPUTERS - Use on multiple devices, Both PC and Mac compatible MULTIPLE SIZES AVAILABLE - Capacity estimates based on average of 1MB per photo. Older photos tend to be smaller, newer/DSLR photos tend to be larger CONTINUE WHERE YOU LEFT OFF - Once you fill up one Picture Keeper, the next Picture Keeper device will continue where the left off