Firstly, I'm sorry about the very poor quality of the pictures. My camera doesn't work, So I used a webcam and that doesn't deal with close up pictures very well. It's some kind of plug. On the nut end it has .50 and 80w and no1 printed on it, followed by the screw, the shiny end is made up of what appears to be brass that has hundreds of tiny holes in it. I found it lying on my driveway, and as it looks important I though I'd better find out what it is! Pictures here (won't let me link images anymore?)
http://imgur.com/CWbejTA http://imgur.com/YRoJu73 Andrew