Sig 556r part. What is it?

I bought a sig 556r and these came in a ziplock bag. Anyone know what they are for?

http://i1244.photobucket.com/albums/gg57...13BB8012E3C.jpg

Ahhhh. Wrong picture. Give me 20 min and ill post correct one. I'm on my phone

Correct pic is up if anyone can help me identify what this is

Posted the pic for you. I don't know what they are.

I just found out after 2 days of searching. They are pirces for the butt stock extension.