These were taken from (going by memory!) a couple of Dell PowerEdge R620 servers a few years back. To be clear, they are just dummy trays to fill a space, not for mounting a drive in. They are removed once a 2.5" hard drive or solid state drive is installed in the server storage drive bay.
Wish to avoid them going to the dump, so thought I'd try here first to see if they're of use to anyone! They should fit pretty much all Dell Servers with 2.5" drive bays that need filling. Thanks :-)