Sonic screwdriver (InstanceTopic, 13)

From Compile Worlds

The sonic screwdriver is one hell of a piece of technology appearing in Doctor Who. It can open pretty much any lock (unless it's "deadlocked", what a cop out) and do a bunch of other cool things. The screwdriver has actually changed over the years, as can be seen in that one episode where the Doctor ends up with two of them, due to time travelling into himself or something - they each look different.