The design is clever. It is like animal waterers I used to use. You put an upside down bottle of water on the top and adjust the nozzle for the water flow you want. I use about 1 drip every 4 seconds. There are three issues. All the plastic bottles I tried were crushed by the atmosphere and just emptied immediately. You need a bottle with strong walls. So I used a quart glass bottle which takes about 8 hours to empty. Second, the adjustment needs to be made every time you fill the bottle. It only takes a few seconds, but sometimes when my hands are wet it is difficult to turn because my fingers slip. Bigger ridges on the knob would help. Lastly, the bottom of the nozzle needs to be above the ground so you can adjust the drip and the weight of the water can lower the stake so it's not. I put a small wooden block under the water holder to keep it up. All easily fixable problems. It keeps my tomatoes soil damp all day in the Texas heat.