Rear of head unit Screw/Plastic/Thingie

[meccano04]

Hello,

Does anyone know what the Plastic cone thing on the back of the head unit is really called, the bit that keeps the head unit at the correct angle in the car?
It sits right in the middle of the unit and ive seen on other cars it can screw off.
I changed the original head unit to a Kenwood and the one from the old Head unit was stuck in, so i couldnt remove it, now my current head unit is sagging a little.

Sorry for the vagueness but i have no idea what it is called

[Say..."Renno"]

Audio Position Locating Pin........

Just made it up....