The Displacement Wristwatch is a device worn by Ray Stantz designed to teleport four spirits to the physical plane in an hour.
As Ray, Peter, and Winston set out to find Egon in the Netherworld, a special wristwatch was put into play. Worn by Ray, it was programmed to extract the four of them in an hour's time.  Once set, it couldn't be readjusted and projected its countdown. When the hour passed, all four were teleported from the Netherworld to Egon's lab in the Firehouse.
- ↑ Ray Stantz (2009). The Real Ghostbusters - "Egon's Ghost" (1987) (DVD ts. 11:12-11:18). Time Life Entertainment. Ray says: "As long as we wear these, it'll bring us back in an hour. And it's adjusted to return four spirits instead of three."