Sorry if someone already said this one, I've been out of town:
2126 - goes on the end of the "powder horns" that hold black power, so that particular amount is dispensed. I think you put your finger over the end, press the lever and invert it to allow the powder to fill up the "nozzle" (my word), let go of the lever and your power charge is ready to pour in the rifle--and only that much will come out. Nice design.I think 2128 is for dispensing honey.
Bill