The Flatline Barrel System is the first production back spin barrel ever produced. Tipmann developed a very slight curve to this barrel that applies centrifugal force to the ball, creating backspin. A spinning projectile travels farther with a flatter trajectory than one that is not spinning. The result increased accuracy and range for your X-7 marker, giving you the ability to hit targets that would ordinarily be out of range. This Flatline Barrel System will add up to 100 feet of flat trajectory to your X-7 Marker. Not compatible with M16, X36 or XP5 conversion kits.