MSD-423 Missile Rack

The Behring MSD-423 "Marsden" Missile Rack is a size 4 missile rack that is able to carry two size 3 missiles.

In-game description
"Behring’s MSD-423 'Marsden' is a complete ordnance storage and deployment system that can be mounted on any compatible size 4 hardpoint for the reliable and effective launch of two S3 missiles."