MSD-644 Missile Rack

The Behring MSD-644 "Marsden" Missile Rack is a size 6 missile rack that is able to carry four size 4 missiles. It is a part of Marsden series ordnance storage and deployment system.

In-game description
"Behring’s MSD-644 'Marsden' is a complete ordnance storage and deployment system that can be mounted on any compatible size 6 hardpoint for the reliable and effective launch of four S4 missiles."