I got tired of the old rubber carboy airlock bungs when i was making wine, so i created this adapter with orings for a tight seal and more stability when adding the airlock. I used 2 #14 O-Rings from Harbor Freight O-ring kit. Size O.D. 15/16" I.D. ¾" Wall thickness 3/32". Printed in PETG with 4 walls and 25%infill for a little extra strength. Working well over and over. Add a little lube to the o-rings to prevent seizing over time!