E&C Devgru N4 Upper Lower Metal Body Receiver M-Lok Rail Handguard System Set For E&C Tokyo Marui M4 M16 Series AEG Rifles AirsoftE&C Devgru N4 Upper Lower Metal Body Receiver M Lok Rail Handguard System Set For E&C Tokyo Marui M4 M16 Series AEG Rifles Airsoft Made out of aluminum. NSR M Lok Rail Handguard with Gen 3 N4 Receiver Kit. Comes with Forward Assist , Fire Selector , Charging Handle , Dust Cover , Bolt Release Catch , Magazine Release Catch , Pin Set , Handguard , Outer Barrel and Gas Block. Outer barrel thread 14mm CCW counter clockwise. Outer barrel length 264mm