|First episode:||"Day 1: 4:00pm-5:00pm"|
|Last episode:||"Day 7: 9:00pm-10:00pm"|
A letter opener was a blunt knife used as a tool for cutting through paper envelopes.
In Alexis Drazen's hotel room at the Palmer campaign hotel during Day 1, there was a letter opener on a cabinet. Elizabeth Nash grabbed the knife and stabbed Alexis in the stomach with it, as revenge for him deceiving her. ("Day 1: 4:00pm-5:00pm")
During Day 7, after Jack Bauer had broken into Senator Blaine Mayer's house, he grabbed a letter opener. When Mayer entered the house, Jack threatened him with the blade and convinced him to help. ("Day 7: 9:00pm-10:00pm")