...As Indiana Jones would say. I am impressed beyond expectation with this piece. It is large--it's as large as the palm of my hand. All shiny brass with pricision engraved and printed lettering with designs. There is a mechanism on the outer ring of the compass; a knob which slides in a slot, the purpose of which is to lock down the compass needle. The box is exquisite, lined with dark green felt on the bottom and inside the lid. It didn't come with instructions, but I really didn't intend to use it. From what I find online, the slanted edge of the gnomon is supposed to be adjusted so it's parallel with the earth's axis. The setting would be your latitude in degrees. The compass is turned so it points north. This piece will be part of my "History of Navigation" that covers from ancient sailing era to the Apollo moon missions and the Space Shuttle! Part of this is the chart magnifier and the perpetual calendar with marble base sold here, This would make a great gift except there's not much area for it to be engraved. It would be a challenge for any engraver. The box is also very impressive and just as much a show piece as the sundial itself.