Hoppe's No. 9 Conversion Adapter Knob End, .38 Caliber Pistol Can be used with patches Compatible with all HOPPE'S cleaning rods Made of quality materials 100 percent designed and tested Hoppe's No. 9 Conversion Adapter permits interchangeability with non-standard size threads Intended for use with .38 caliber pistol This is a great, easy to use adaptor