Shop › MIDWEST G4M M-LOK 13.375" HNDGRD BLK MIDWEST G4M M-LOK 13.375" HNDGRD BLK $201.95 Midwest Industries Gen 4 M-Series Handguard, M-LOK, Fits AR-15 Rifles, 13.375", Black MI-G4M13.375 Quantity: Add To Cart Added! Midwest Industries Gen 4 M-Series Handguard, M-LOK, Fits AR-15 Rifles, 13.375", Black MI-G4M13.375