Combining the Ultra Jags and Best Bore Brushes into one convenient 26-piece set gives the ultimate storage system for brushes and jags. Neatly organized in a durable, hinged box with marked cavities, it's easy to select the correct jag and brush for your particular application. Because they are caliber-specific, you can be assured of an optimum fit to your firearm's bore for efficient and thorough cleaning. All jags and brushes have 8-32 threads. *Does not include 20 caliber; 17 and 20 caliber has 5-40 threads and is a standard bore brush.