Prairie Dog 6-120 Perfect Powder Flow Control Fits Dillion Powder Bars A Simple Turn of the Knurled Thimble will Move the Anodized Aluminum Sleeve over the Numbered Stainless Steel Measuring Spindle to the Next Graduation Each Graduation Mark Represents a Change of .002" to the Opening of the Powder Gate on the Powder Block A must have Reloading Accessory for Dillon Owners to get Accurate and Consistent Loads that Improve Shooting Accuracy Use with the prairie dog Perfect Powder Baffle to Achieve the Most Accurate and Consistent Ammunition you can Assemble