Proton cannon (Earth-5875)

The Proton cannon is a poweful anti-aircraft weapon of forerunner design that is featured on the Reapers.

Description
A powerful directed-energy cannon, the proton cannons are mounted on both the monocular visor of the Reaper or its four-legged chassis. Highly accurate and powerful, they fire 20,000 gigatons of pulse-laser energy that can tear warships apart.

Many of these cannons were used by the Reapers during the Subjulgation of Eart and their assault against the occuppied locations of the Orion Arm of the Milky Way galaxy.