For Regular Mouth (2 3/8" inner diameter) Mason jars.

The plastic cover has a little tab to pull it open. Close it while grinding to keep the beans from jumping out.

Also grinds hard spices like peppercorns. Does not work well with soft spices, flax seeds, or nuts.

The grinding mechanism is a ceramic burr. Clean by grinding uncooked white rice.

To adjust the grind size:
Remove the top black nut, the spring, and the round piece under the handle.
Screw the hexagonal piece up and down the threaded rod. You will see the 2 pieces of the ceramic grinder moving closer or farther apart. Reassemble and grind.