The new Russian Kontakt-5 ERA is not completely destroyed when hit - it still functions as armour after exploding.
Anti-tank weapons work by piercing the armour and exploding inside, thus killing the crew.
Explosive reactive armour counteracts the force of the explosion by creating another explosion on itself. Against shaped charged missiles, this type of armour really comes into it's own.
The design was patented by Manfred Held in the 1970's.