I used one of those parts on a DIY external reactor. Works like a champ!

"Dave" wrote in message
...

At most LFSes (inc. PetSmart) you can find "Lee's Discard-A-Stone"
airstones. See: http://www.marinedepot.com/a_ap_lees_as.asp

These are discardable airstones that come with separate plastic barbs; if
you were to use an airstone, you would fit one end of the barb into the
airstone and the other end into your tubing. One end has a (what's the
term I need) collar which would normally seal the end of the airstone.