Another review by Bruce of BB2K Airsoft and this covers the Lonex F4 FM SR BAW AEG. As this is done in German, click on the language caption shown in the player to watch and listen in English... "The Lonex L4 FM SR BAW is an electrical M4A1 replica of solid metal. The system operates with the BAW. The Blowback Adaptive Weapon system generates a strong recoil effect by an additional bolt, located in the Stocktube. When shot, the bolt snaps back and generates the kick."