My family and I went on our first MD'ing hunt this weekend. There had once been a house built on the site by my wife's Great Grandfather. the family estimates the house was built over 100 years ago. The house has been torn down for some time now. I just got my first detector this week. It is a Ace 350. Any way, we found this item and none of us knows what it could be. It is approximately 5 to 6 inches long and is heavy. it also has 48-52 written on it. I don't recall what reading it showed on my Ace.