The G&G CM16 Raider 2.0 is an updated version of the legendary G&G Combat Machine Raider. It features a polymer M-Lok Rail system and an updated receiver. The stock is fully retractable and is where the battery is stored. It has a nice ergonomic grip and a quick trigger response. The top part is a picatinny rail from the rails to the receiver with a flip up front and rear sight. You can flip it down when using optics.