Mine was loose for a bit till I realized I didn't have it on correctly. Make sure it is oriented correctly and snaps in. Also, the HU may be pushed too far back against the OEM sleeve. I reused my OEM sleeve with my Alpine HU and had to 'finaggle' it a bit to make it sit correctly.

 

Mines a bit loose.
It doesn't fly off or anything but ita very easy to pull off.

My original one broke so I ordered replacement.
I figured it was just a crappy copy.

 

two thoughts..


1. make sure the head unit is pushed all the way in
2. it has been a while but i thought there were clips on the top and bottom but it has been a while so i could be wrong...having said that, mine can still be pulled off pretty easily if i wanted to take it off...

 

I have the CDA-117, and the piece is loose, but doesn't fall off or anything, It's simply a "filler" piece so if yours is loose to the point that its constantly falling off, then I would just scrap it, but make sure the clips are lined up first (as previously stated, it could be upside down).