Install on your progressive press after the powder drop station to automatically check dropped charges. Checking powder charges on your progressive press can be difficult, and is sometimes ignored, even though it’s a smart practice. Hornady uses a similar device on our own ammo manufacturing presses. It won’t replace careful attention, but helps monitor the reloading process. Works with all powder types and cartridges.WARNING: Discharging firearms in poorly ventilated areas, cleaning firearms, or handling ammunition may result in exposure to lead and other substances known to cause birth defects, reproductive harm, and other serious physical injury. Have adequate ventilation at all times. Wash hands thoroughly after exposure.