Sly have long had a good name in barrels andthe Dual Carbon kit keeps this reputation in tact. Before now i've used stock barrels and i've upgraded to a un1tech with some different bore tips and i'd found them to be better than the stock (due to being able to match paint to the bore size perfectly depending on the paint of the day) however once i put down my first lane with the sly kit the un1tech was blown out of the water. The sly Kit works with different bore backs and a single tip (the length of which is up to you when you order). I opted for the 14' barrel as i think 12' is too short and 16' is too long. The kit comes with 4 backs (.683" .686" .689" & .692") and in these along with your stock barrel you'r bound to find a bore that matches whatever paint you'r using. I ordered it from ***Oringmonkey.com Oring Kits Paintball Marker O Ring Kits*** (check his stuff out ) and it arrived the next week excellently packaged etc etc. I brought the kit out onto the field after matching the bore to the paint i was using for the day and during the one of first games i put a lane down and got a kill in the first 10 secs of the game. The accuracy of this barrel has amazed me. I've only had one break so far and it shot through cleanly enough. That said i'd not want to leave a break from the first point in the barrel through for the rest of the game. When ordered from oring monkey, a barrel wrap is included which makes bringing your barrels to and from games easy and it keeps them safe from scratches etc Personally i'd give these barrels a 4.5/5 as the high price tag ($180 on oring monkey) they could be out of the reach of the budget paintballer. Other than that i highly reccomend this barrel system.