I posted this way back and promised to repost due to requests. It is all Stainless Steel, uses six drops of Mercury and the one I have was made by my Great Uncle back in the 50's.
This unit works as a Pendulum Dowser or as a Long Range Dowser. To help tell the different types of wobbles it gives for different metals, I suggest you try each item separately and note how the dowser reacts.. Kinda like you would do with your detector.
To help locate items from a distance use triangulation to find the approximate location then fine tune from there. I use mine with a camera tripod that collapses into a 12 inch section. Makes it easier to transport in a small backpack (along with bottled water and a couple of snacks and my digging tools) and carry my detector at the same time.
Good luck to you and I look forward to seeing how it works for y'all. I hope to head Northeast one of these days (maybe while on a rock run) and try mine out with Bert-Bert and Pappy...
James