The conveniently packaged Tipton 13-piece caliber-specific set of Ultra Jags means you always have the right jag at hand. Contained in a durable, hinged box with marked cavities, it's easy to select the correct Ultra Jag 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. 17 to 45 caliber (does not include 20 caliber). All jags have 8-32 threads (17caliber has 5-40 threads). 13 Piece Caliber-specific Set Of Ultra Jags Contained In A Durable, Hinged Box With Marked Cavities Contains .17 - .45 Caliber Jags Have 8-32 Threads .17 And .20 Caliber Have 5-40 Threads