The tremstopper device allows the user to lock the whammy bar by the simple twist of a knob, hence turning the Floyd Rose bridge into a fixed bridge system. Example of a fixed bridge system would be the Tune-o-matic bridge.
Tremstoppers can also be referred to as trem blocks. Blocking the trem, or tremolo, on a floating tremolo (such as a Floyd Rose)can be done with a variety of objects, but it is best to use wooden blocks. To block the trem with wooden blocks, cut them down to size so they fit behind the cover plate, then wedge them on either side of the trem block so it cannot move either way. This makes the bridge unable to move and effectively converts the floating bridge to a fixed bridge. If done properly, it eliminates the tuning problems and difficulties this type of bridge has, but means you cannot use the whammy bar.