This is the spring claw that you always find in the spring cavity on the back of guitars that use a fulcrum tremolo system. Standard Stratocasters with a tremolo are a good example of a fulcrum system with a back plate and spring cavity. You can attach up to 5 of the 8414 Fulcrum Springs on it. 2 mounting screws included.
Fulcrum systems pivot behind 2 posts like the Kahler 2500/2520 Traditional, 2710 Killer (2700 Series), 2720 Spyder, 2760 Steeler as well as Floyd Rose, Wilkinson, Fender etc. If its got a back plate, then its a fulcrum system and this claw holds the springs.