This is a bracket to mount a Bench DMM under a shelf. Its compatible with: Owon XMD3041 / XDM3051, Farnell Multicomp Pro 730027 / 730028, Peaktech P4095 / P4096.
The closed variant is more rigid (the open version tends to open a bit under load), but its more fiddly because you should attach the cable before.
When the DMM moves when you use it, glue the stiffeners between the front and rear bracket to hold it in place.
The author hasn't provided the model origin yet.