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, its 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 firearms 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 JAGSCONTAINED IN A DURABLE, HINGED BOX WITH MARKED CAVITIESCONTAINS .17 – .45 CALIBERJAGS HAVE 8-32 THREADS.17 AND .20 CALIBER HAVE 5-40 THREADS