The SIG 556 AEG is Sig Sauer"s take on the beloved carbine rifle (M4/M16/AR15) used extensively by the U.S. Military and by many other law enforcement/military agencies around the country and around the world. Sig Sauer, manufacturer of some of the highest quality firearms/pistols in use today, has put their name on a QUALITY product. The SIG 556 Airsoft AEG is no exception to their tradition of excellence, as it is realistic, functional, powerful, accurate, and BUILT TO LAST (high quality construction inside and out). The full metal construction is superb, with excellent balance and a flawless finish. The full Sig Sauer trademarks are laser engraved into the upper receiver, and stamped into the motor grip. The polymer composite construction of the hand guard, stock, and motor grip makes this rifle feel exactly like its real steel counterpart and adds to the overall durability of the AEG. Aside from being one of the most rugged AEGs on the market, the NEW SIG 556 is also very ergonomic. It features a wide contoured lower hand guard and a rubber butt pad plate, which makes shouldering the rifle very comfortable. The Sig Sauer 556 AEG licensed by Cybergun is one of the most durable, realistic looking, and ergonomic full metal AEGs on the market . We strongly recommend that you use King Arms .20g or heavier BBs for optimal performance.