FAQ: What is Item Level Synchronization?
"Item level synchronization" means that if you make changes to cards in your wallet on both the PC and the location you are synching to, all of those changes will be retained when you synchronize.
Each card in your wallet is synchronized, as opposed to the entire file (all of your cards at once) being synchronized.
If you change the same card on both your mobile device and your PC, eWallet will duplicate the card when you synchronize to preserve your information. One of the cards will contain the information from that card on your desktop, and the other will contain the information from that card on your mobile device.