These EcoPlus Air Stone Discs are great to put at the bottom of your reservoir for aeration. Quality construction with foam feet to reduce vibrations. Use with 3/8' tubing (will not work with the smaller 1/4" air tubing). Great for making your own 5 gallon compost tea brewer. 
 
Compatible with 3/8 in ID x 1/2 in OD Clear Vinyl Tubing (will not work with the smaller 3/16 in ID - 1/4 in OD tubing found in most pet stores). If you heat the end of the tubing with very hot water you can also get by with the 1/4 in ID x 3/8 in OD tubing; this is how we use the Commercial Air 3 Air Pump along with the 6 in Air Disc to make our 5 gallon compost tea brewers.