Hole Tidy / Wall Grommet.
Semi opaque to blend in with your decor but it is also paintable if required.
The double version of hole tidy is for Twinsat type double cable.
These are for the inside to make the install look neat, they are not for any form of waterproofing or to go outside as they would force the cable to go into the wall perpendicularly rather than in a downward curve (which is preferable).
Internal diameters :
Single = hole is 7.5mm (8.0mm is a tight fit).
Double = hole is 7.5mm (8.0mm is a tight fit) x 15mm.
Size of required hole in the wall :
Single = 10mm
Double = 16mm