Hoppe's 9 Knob ends .22 Caliber Rifle. OpticsPlanet Inc is an Authorized US Distributor for Hoppe's 9 Cleaning Kits. Permits interchangeability with non-standard-size threads. Specifications for Hoppe's 9 Knob Ends: Manufacturer: Hoppe's 9 Gun Type: Rifle Features of Hoppe's 9 Knob Ends For .22 Caliber / Gauges For Cleaning Firearms Use with Patches Compatible with Hoppe's Rods Package Contents: Hoppe's 9 Knob Ends Hoppe's 9 Knob ends .22 Cal