Chosen Solution

Can anyone tell me what this piece of plastic does. I did did some upgrades to my 15" Mid-2010 MBP and found this piece to be broken. Do I need to replace it, and where can I get it? Please see picture at http://imageshack.us/photo/my-images/94/

that clip attaches to a nub that sticks out from the inside of the bottom case. It does not need to be replaced, however the bottom case will have more flex to it if you do not replace it. look up ebay item number 250711661655 for a replacement. The only ones I see available are in the UK.