The Umarex Elite Force 6mm BB are specially designed for high end scenario tactical and military airsoft gaming. They are the highest quality BBs currently on the market, and are designed for the serious player. The BBs come in both .20 gram and .25 gram versions, for precision airsoft games. Perfect for milsim and police force training. The G17 Gen4 comes in airsoft field safe at 290 FPS with a .20 gram BB.