HI, This is the Tippmann Flatline Barrel System for the Model 98 or Custom 98.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 increased accuracy and distance but also offers flat trajectory for thick brush and canopy play. By minimizing trajectory of the ball and increasing accuracy, you increase the amount of targets which would ordinarily be out of range. This Flatline Barrel works great and has only been used in 3 games (thats about 200 balls none of which broke). The reason I'm selling it cause I don't like being a sniper anymore. I take PayPal and money orders only. Please feel free to email me with any questions about this item or if you want to know the shipping cost send me your zip code.