GHK did say they are releasing 3 versions of the AUG. The traditional A1, the flat top A2 and the quad railed A3 and that raised a few eyebrows. This A3 isn't heavy, but has a very solid build and feels so much better than all its AEG counterparts with a sturdy polymer body with a slightly grainy texture that is not going to scratch anytime soon. Now apart from the charging handle, grip and magazine, everything else in front is made out of metal. Apart from the sling points in front of the scope and on the left side of the stock, nothing rattles, not even the 30 round magazine which look exactly like the AUG mag should look like. The build is impressive. realistic operation solid construction hard kicking blowback action This product is only compatible with gas designed specifically for Airsoft guns. Do not use lighter fluid or butane gas, as that will cause permanent damage.