The Acculock Barrel Kit is the result of more than a year of design and testing by one of the world's top professional paintball teams, San Diego Dynasty. When setting out to create our new barrel kit, we wanted to do something that was different and better than what was already out there. After countless hours in the design room and a strenuous testing program that included an array of paintball formats and environments, we at Field One Paintball have developed a new barrel kit that we think is superior to other products on the market. The revolutionary AccuLock Barrel Kit includes 6 control bores ranging in inner diameter (I.D.) from 0.675 to 0.695, so you can get the perfect fit for any paint. The design, finish and overall quality of the AccuLock Barrel System combine to offer you unrivaled accuracy and dependability. Our patented self-aligning feature ensures you will have the perfect fit between control bore and tip every time. Traditional inserts are very fragile, so we designed our threaded control bores to be more durable. Our control bores lock in place, with our new patent pending design, so there is nothing "floating" and inserts won't accidentally fall out. The kit includes smaller ID control bores for fitting with higher quality paint to give you the best efficiency and consistency. The kit also includes larger ID control bores to minimize ball breaks in the barrel by "over-boring" with lesser quality paint. 14" overall length. 6.75" control bores. AutoCocker threads only. AccuLock Barrel Kits come protected in a semi-rigid zippered case that fits all components of the barrel kit while not in use. Free Shipping!!! All AccuLock Barrels are backed by the "AccuLock Lifetime Insert Replacement Program".