So this was rattling around the inner boot lid cover. Any ideas before I bin it?

 

just installed new rear camera for dash cam and was curious what the rattle was since we had had it. 

Is there a small, round hole in the narrow end? My guess, insulating sleeve for a push-on blade type electrical connector.

There is a small hole in the end. Looks like the “nipple” end has been rubbed a lot. 
 

insert bad jokes here.