Cool File, Bro

Cool File, Bro is an achievement in Halo: Reach. It is unlocked by recommending a file to another player. It is represented by a green hand showing a thumbs-up gesture over a five-point star, similar to the fist and star found in the Pummel medal.

Trivia
The title is referencing the internet meme "Cool story, bro!", which is a sarcastic method of showing indifference to someone's story.