Energy emitter l-3

"Beam emitters pool their energy within each arc, so the more emitters you have facing in the same direction the longer you will be able to sustain a continuous beam in that direction. With enough emitters you can sustain larger beam types for longer periods."

This is in the largest variety of beam emitters and is capable of pointing any any of the cardinal directions. Multiple emitters mounted in the same direction will pool their capacity allowing larger beams to be fired and allowing a beam to be sustained for longer periods.