My DIY drippers are much more reliable then the ones with the spigots. I took a washed tall deli cup and filled it with water. I then cut a piece of old towel, 1 inch wide, double the length of the cup plus a couple of inches so the piece of toweling could lay in the bottom of the cup, go up over the top of the deli cup and down the side to the bottom of the cup on the outside. Try it first by letting it drip into your sink. You get a nice steady dripping, not too much, not too little. VOILA. It doesn't stop dripping until the water is gone.
All my cages now have these DIY drippers and I love them. So do my chams. BTH, you can use any container, I started with 1/2 gallon milk jugs and just cut the tops off. Just make sure your piece of toweling is long enough.