These go onto the end of the springs before being inserted into the Spring Tubes. They will be on the end that goes into the Spring Tube FIRST so that they are between the Rear Case pin and the spring (towards the front of the binding). The Spring Tubes are what the Rear Case slides on, and part of our patented Sliding Plate system. It is crucial to have this part on the end of the spring that moves back and forth with the Rear Case.
Spring Kits, both standard and soft, include a set of four (4) these.