Ziss - Adjustable Airstone

This is one the best air stones out there. It is weighted to sink naturally and can be taken apart if it ever were to clog - so it can be cleaned or the disks replaced. It also works great inside sponge filters. Instead of replacing a cheap ceramic air stone every 4-6 months as they get worse and worse for bubbles, install one of these once and nearly never worry about it again. Tighten or loosen the disks to change how big the bubbles are.