This is the PVC cover for female spade connectors. These are used in different locations in the harness. They are mated to the female version of this. Examples would be on the Interior Harness and where it meets the Main Harness (a Black with White tracer wire) or on the Rear License Lights Harness meets the Main Harness (a solid grey wire). There are other applications as well; including where you would think where a shrink wrap cover would be. Please email if you would like the exact locations. There are a total of 4 males that use this cover on the main harness of a 65-68 harness. The second picture below shows how it connects with the female spade cover.