National Metallic Brass Cleaning Media is an excellent choice for wet tumbling dirty handgun and rifle brass. This cylindrical shaped, corrosion resistant, stainless steel media provides reloaders a proven method to clean primer pockets and polish cases. This high-quality stainless steel media comes in a reusable twist top plastic bottle allowing you to easily pour it into your rotary tumbler. Next time you go to your workbench to clean brass, make sure to use the National Metallic Brass Cleaning Media. Note: Not for use in vibratory tumblers. This media is designed to work with rotary tumblers, such as the Lyman Cyclone, Thumler's Model B, the Frankford Arsenal Platinum Series or the RCBS Sidewinder. It is not designed to be used in vibratory tumblers. FeaturesExcellent Cleaning PowerCorrosion ResistantCylindrical ShapedMagnetic