I use these to aerate and add oxygen to increase pH is a spa environment. I need a few of these and was cautious after reading the negative reviews, but I've been using 2 of them for about a month now and they work very well, so I ordered 3 more. The holes are very tiny which is perfect since smaller holes produce smaller bubbles which help in the oxygenation process better than larger bubbles. The tips are plastic and I can see them breaking easy if you aren't careful, but so far no problems for me. Definitely worth $10 a piece!