This is a rubber (foam) stunt Mark IX tricorder made and used at the time of First Contact and would have been available for subsequent use in DS9 and/or VOY.
This particular tricorder is missing nearly every greeblie (clear lucite bar on edge still attached) and is missing every sticker.
It is a one piece so the tricorder does not remove from the holster.
This is one of two stunt tricorders of this type in my collection.
I am told the stunt men were not fond of the metal hooks used to secure this type of prop to their costumes (jabbing during falls) and much preferred when a switch was made to velcro.The offending metal hooks.