Do you have the Eachine Moneagle FPV Monitor and found the mount insert didn't quite fit your radio?
I have redesigned the rubber insert to fit smaller handle diameters (based off of my RadioMaster TX16S handle without the grip add-on)!
Fits tightly inside the monitor holder with a cutout to allow easy attachment/removal. I printed mine with Hatchbox TPU for flexibility as PLA/ABS will be too rigid. Adding a bit of electrical tape on the inside and around the handle helped with grip as the smooth surface still slid around the steel rod. Silicon would also be a more permanent and cleaner post-process option for this issue.