FREAK® XL Stainless Steel Boremaster KitThe Freak Insert is at the literal core of the Freak barrel system. Paintballs can change size from thousands of variables; temperature, humidity, elevation, storage conditions and manufacturers to name a few. The interchangeable bore system allows players to adapt to whatever paintball throws at them. The stainless steel Freak Insert is the toughest interchangeable bore available for paintball. The Stainless Steel boremaster kit includes: . 677 . 679