PDA destroyed by Theo Stoller after being betrayed by CTU.
A Personal Digital Assistant or PDA is used to keep schedules, get on the Internet, possibly make telephone calls, view maps or satellite images, among other tasks. Technologically advanced PDAs, like Jack Bauer's Palm Treo 650, is able to receive and send messages, pictures, and more. Chloe O'Brian was able to tap into it and send out a certain frequency at the beginning of Day 5, causing a bomb to go off at the Ontario Airport. Chloe also helped CTU tap into a PDA that was being used by foreign spy Theo Stoller.
During Day 6, information recorded in Lisa Miller's PDA was being downloaded by Mark Bishop and given to the Russian government.