At only 2.75 inches in diameter, the Direct Attack Guided Rocket - DAGR, pronounced dagger - is designed to be the bread-and-butter air-to-surface weapon in the US arsenal. It's compatible with every flying thing, very low cost, extremely precise and extraordinarily deadly.
The secret is its elegant simplicity and delayed fuzing of its 4.5kg warhead, which according to Lockheed Martin "increases the DAGR rocket's lethality and reduces collateral damage". Instead of detonating at the time of impact, the missile penetrates the armour or the building, detonating inside. That means that it kills everything that is inside without necessarily damaging stuff around the target.
Lockheed Martin has now finished testing this on multiple helicopters, like the AH-64D Apache, AH-6 Little Bird or the OH-58 Kiowa Warrior, but it can be mounted in anything currently supporting Hellfire II missiles. Not only that but, while not as destructive as the Hellfire, you can pack more rockets in the same space.