The Hornady 366 Auto Progressive Shotshell Press Powder Bushings are great for fine tuning your shotshell load. The interchangeable charge bushings are designed so shot and powder bushings cannot be accidentally reversed in the charge bar. Machined from solid bar stock and reamed.Technical Information:- Fits: Hornady 366 Shotshell Presses - Use: Powder Bushings to Measure out Different Charge Weights- Material: Aluminum