It's a Coin Dropper. A motor-driven device crafted from brass that automatically drops four half dollars, one at a time, into a drinking glass. The device was designed to be concealed in a pack of cards.
A version of this effect called Robot Coins was sold by Tony Spina during his tenure at Tannen's Magic Shop in New York City. Then later his partner John Blake created a version called Descending Dollars when we ran East Coast Magic.