Lots of things can cause a squeaky floor. The solution is to lock the offending piece of flooring into a position where it can't move anymore.
Squeak-Relief does this from the underside of the floor. A small aluminum bracket is screwed to the floor joist, then a second screw pulls the subfloor down tight. The whole process takes about 60 seconds!
Each kit includes the required Phillips drive screws (1-1/4" and 3") and two Squeak-Relief brackets - enough for two repairs.
Only one bracket per squeak needed.