What are the 3 bumps/ridges on the green flex barium nozzles for?

I have been looking at the larger (usually green) "Barium type" or "plastisol" or "N-Tip" nozzles and wondering why they have the three ridges or bumps under the head. For play they definitely can add to the stimulation if it is wiggled or thrust in the anus, but I doubt that is the original purpose. It could be "measuring" to see how far inside the head is, but that doesn't make much sense. Does anyone know?

Picture of the nozzle here:

https://en.zity.biz/index.php?mx=gallizz;ox=imagedownload;image;img=287497

My guess--and that's all it is, a guess--is that the three bumps allow the administrator to see how deeply inserted the nozzle is.

I had that type of nozzle at one time in the past. I didn’t really like the nozzle and found I found the ridges annoying so I got rid of it. The ridges may have been added just for cosmetic purposes to make it look more exciting.

Just my thoughts ... just like a bolt with threads. More surface tension for better retention.

Honestly I have no idea what they are for, but I've had that nozzle in the past and somehow lost it. It was one of my favorites and most comfortable. I've tried to find it on enema supply places like optimal health website but they say it's been discontinued. If anyone has any idea where I might find it please let me know. Send me an email. Thanks 🤠 🏳️‍🌈