Hi.
I contacted Redbyte. This was their answer. Tryed it, and it's not that good fit actually. I'll probably go with velcro.
"It is mounting bracket, that is used to mount the Decimator to the back of a rack, behind the monitor. A picture is attached, showing it installed.There are two slots on the back of the box that have threads for attaching it with two M3x6 screws."
Bye
/marco