Tippmann A-5 Flatline Barrel With Built In ForegripThe Flatline Barrel System is made exclusively for the Tippmann A 5 and 98 Custom. The new style Flatline gives you a more realistic look while providing you with a built in foregrip. The Flatline Barrel System is the first production back spin barrel ever produced. The principle behind the system is Tippmann's newly designed slightly curved barrel, which applies centrifugal force to the ball, creating backspin. Not only does this system offer