You adjust a "V" on the powder measure rod. The buzzer has a pin that aligns to the V, if not aligned, it buzzes. I watch where the buzzer fits in the V, if it looks low, you can measure it. It will definitely alarm on no or double powder. It will alarm at low or high powder also. I've never tried to put a hard number on it, but yes it will alarm on a squib. When I used corn cob media, I've had a few that had a small amount of left over media in a 5.56 brass, it alarmed and gave me a good reason to check out the load.