An early iron prosthetic hand, similar to the one famously worn by Götz von Berlichingen.
This is a slightly later specimen, given the more lifelike mold of the hand. More images here.
Made entirety of iron, with a hollow, naturally modeled hand furnished with a movable thumb and paired fingers, internal ratchet mechanism and external push-button release, and a tubular socket comprising of a long outer plate fretted with a pattern of repealed chevrons, and short inner section formed of plain and scalloped riveted strips, each fitted with buckles for the attachment of a harness.
The replacement hand created for Götz had a cruder, more robotic appearance, though it still enabled him to hold playing cards, a feather quill, reins, or a lance– everything a feuding knight needs.