Where cable needs to enter a panel, we use round TPS (not unlike "flex", it just has a thicker sheath).
The Gland used to effect that way through, into what might be an IP (Ingress Protection) rated enclosure, has a rating of IP68 (Dust-proof/Submersible).
I've never liked the idea of a clamping force on cables that are not round, not being circumferential.
There is potential for insulation migration, over a period of time
