Sidewinder "Ex-Wife" Missile

"I got something special for this guy. I’m gonna bust his bunker with the Ex-Wife."

- James Rhodes The Sidewinder Self-Guided Missile, also known as the "Ex-Wife" Missile, is a projectile designed by Justin Hammer.

Iron Man 2
When Justin Hammer gave a presentation to the United States Armed Forces of the different weapons his company could potentially add to the War Machine armor, the Ex-Wife Missile was marketed as the best available.

Battle with Whiplash
During his battle against Whiplash, James Rhodes chose to deploy the Ex-Wife Missile against him; it turned out to be a dud. Iron Man laughed, "Hammer Tech?" as he watched the inferior weaponry's failure.

Powers
This missile is a kinetic-kill sidewinder with a secondary cyclotrimethylenetrinitramine (RDX) burst, which means it is designed to be fired from long ranges and its kinetic energy allows it penetrate armored targets. It then detonates with a force equivalent to that of C4 as RDX is a main component of C4 explosive. It is essentially a miniaturized dual-stage smart bunker-buster with a high explosive yield.

Despite its fearsome reputation, it ultimately failed to function properly when used by James Rhodes in the War Machine Armor: Mark I. This was likely due to the short range at which it was deployed, lacking the time needed to build up enough velocity to penetrate its target and prime its explosive charge.