Easy to make and far cheaper than the commercial variety. Works with a standard aquarium air pump. In addition to printing the drip ring, you will need:
14" PVC pipe 1/2" OD with a 45 degree slant cut at one end
14" Clear Vinyl Hose 1/2" OD 3/8" ID
15" Clear Vinyl Hose 5/16" OD 3/16" ID
1 x Aquarium air pump
6' Air pump tubing
Basically, the the the thin vinyl hose goes inside the thick vinyl hose all the way down until there's about 1/4" to the end of the outer hose. The end of the thin hose needs to be completely contained by the outer hose, but as close to the bottom of the bucket as possible. The air pump hose gets jammed into the wide hose at the top along with the thin hose and try to get it down inside a good 1/4". Try to orient the thin vinyl hose and the air pump hose so that their natural curves point away from each other. You should have about 1" of thin tube and 6' air pump hose sticking out the top of your wide hose. Completely cover that end with E6000 and allow to harden for 24 hours before use. Then, pop the drip ring on the end of the thin vinyl tube and slide the entire wide hose assembly into the PVC with the slanted end at the bottom.