Sometimes you decap and sometimes you don't. What happens when your decapping pin is broken and you don't realize it? How about that stubborn spent primer that hangs onto the pin and isn't fully discarded, only to be pushed back in by the swage station? Oops. This is a must-have accessory for your Mark 7 Press. The positive decap sensor uses optical recognition to determine if a spent primer is removed, and if no spent primer falls the machine stops after the stroke, making it easy to remove the impacted case. Save yourself and save your machine. If you are processing or loading new brass, simply disable the sensor from the Mark 7 tablet interface. The DecapSense ALSO acts as a brass sensor - when enabled it can stop the press when brass is not present in the decapping station.