This cap fits essential oil bottles (18mm diameter neck)
Ribbed side, not flared skirt, it is tamper evident
its supplied as two pieces - you push the dripolator insert into the bottle and then screw on the cap.
the dripolator insert has one hole in the middle; nominally called "high-flow"
Please ensure your packaging solution is tested before you go to market. Don't assume your eg bottles and caps are a neat fit until you've really stressed them.