Tipton Ultra Jags use an innovative technology of nickel plating to satisfy the shooter who wants the best tools to maintain their firearms. The nickel plating will not scratch or harm the finest bore. These cleaning jags are constructed from a solvent-proof material. When you use Ultra jags, you'll get better, faster cleaning results because you'll know your getting blue stains from copper fouling from your barrel and not from the surface of your jag. In addition, you will increase the life of your jag by protecting the jags brass core from the aggressive modern solvents with the nickel-plated coating. (17-20 Caliber is 5-40 threaded all others are 8-32 threaded).