3 Picatinny Hand Guard Rails System For MP5-SD Now you can upgrade your MP5SD with a full Picatinny handguard system. Designed and manufactured for a 100% secure fit. Provides a stable mounting platform for Picatinny accessories. Lower rail – ideal for forearm grips. Two side rails – ideal for lights, lasers and other mounts. To fit reflex sight, it is recommended to add one of our #TR5 upper rail famely