The 2 inch diameter by .25 inch thick Iron Man 3 Arc Reactor Glowing Pewter Keychain is an awesome way to keep your keys together while showing off ones affection for Robert Down....err I mean Tony Stark! I dont know how I could possibly get those two confused. If the Iron Man 3 Arc Reactor Glowing Pewter Keychain isnt cool enough for you as is this baby also glows in the dark! Probably a side effect of Extremis or something like that.