A Screwdriver is a hand tool used to tighten or un-tighten screws as fasteners. Flathead screwdrivers can also be used to pry open small doors.
While on the H.A.R.M. Underwater Base in the Aegean Sea, Cate Archer had to use a Screwdriver to open up an access hatch to the fire suppression system. Once this door was opened, she was able to activate the system to put out a nearby fire.
Screwdriver on Wikipedia