These are two TOS communicators from the original Star Trek. There are many version of this communicator out there. Here are two of the more "popular". The first picture is a kydex body which has a flatter black finish. The second picture is a side-by-side comparison with a Horch model (the name of the person who rebuilt them for a DS9 episode) with a more glossy finish. Both feature a working moire pattern which is built upon a stopwatch, just like it was in the tv show and is controlled by a small brass rod in the bottom.