Lee's wooden airstone and i crimp the tubing and rubber band this part to create a little pressure. Don't wrap too tight, have a solid bottle as well i use a big cranberry bottle, and i release with a bamboo skewer, insert into crimpp to get desired level of flow and place airstone beneath my in tank or internal filter(aqueon 15 gets job done) already had it.. and i use one tablespooon yeast 2 cups sugar, fill bottle 85+% of way but not full, maybe less first time to watch bubbling over. No bubble counter no extra bottle here. But beware of shepherd puppies knocking your bottle over. Get it out the tank fast before yeast and alcohol and sugar get in your tank and cause algae. Which my fake Ottos (cae) loved