MSD-341 Missile Rack

The Behring MSD-341 "Marsden" Missile Rack is a size 3 missile rack that is able to carry four size 1 missiles.

In-game description
"Behring’s MSD-341 'Marsden' is a complete ordnance storage and deployment system that can be mounted on any compatible size 3 hardpoint for the reliable and effective launch of four S1 missiles."