Easy to use and it works well. I fill about 100 1oz bottles of oil at a time with this. It fills by time, not by volume. So the thickness and temperature of your liquid will determine the amount and weight that is put out each time. You just make small adjustments for each batch and it's fine. The margin of error is within 0.3 of an ounce for me. So I still weigh each bottle after I fill it, just so i know for sure. It definitely beats pouring each bottle by hand. I can fill 100 bottles in about 20 minutes.