I needed a grommet to allow 29 Ethernet cable pass from my roof into a cabinet to connect to patch panels. The plug fits snug in a 54mm holesaw hole through 13mm plasterboard.
The design includes 2 parts, a plug and a locking ring. 4 grooves facilitate the locking function.
Design works, but was hard to produce the force needed to lock the two parts together, a better approach would be some form of twist lock.