Phalanx CIWS
A number of Flight IIA ships were constructed without a Phalanx CIWS because of the planned Evolved Sea Sparrow Missile, but later the Navy decided to retrofit all IIA ships to carry at least one Phalanx CIWS by 2013. The 60 kW High Energy Laser and Integrated Optical-dazzler and Surveillance (HELIOS) will be tested on an "Arleigh Burke" ship in 2021.