The RCBS Little Dandy Powder Rotor comes in 28 different sizes, and they are all interchangeable. These powder rotors precisely measure the right volume of powder for up to 400 different loading combinations with the RCBS Little Dandy Powder Measure. The RCBS Little Dandy Powder Measure works with all kinds of smokeless powders, and you will never need to readjust the measure after changing out the rotor. You also have the option to use the tool by hand or mount it on your reloading bench to use it with an RCBS powder measure stand.