The solid block of lignum vitae wood has been shaped on a lathe to the form of a hat mold, and then modified by having stump of an old, shortened file driven into the top. The purpose? To create a comparatively elegant “oyster block by which the edge of an oyster can be held against the top of the dully sharpened edge, and then tapped with a hammer to open the critter. I’ve opened a lot of oysters in my life, and wish I had this device in those days. If you search for oyster blocks on the internet you can find that they usually are used to knock off the lip of the shell, exposing the innards so that a knife can be inserted to cut the adductor muscle. This one splits the oyster wide open, as can be seen from the shell marks on either side of the blade. The lignum base of the tool stands 5 inches high and is 5 inches wild. The bluntly edged file projects another 3 ½ inches high, and has an edge 1 ½ inches long. This is a great lignum tool for display, or even use. It is a great whatsit item for the shop or office. Fine.