Pete Shew wrote:

ISTM that, especially the screw ones, are much more forgiving on difficult
surfaces than the plastic ones with an obo(?) nail on one side.

If you're putting the latter clips into brick/masonry, there are small grey
plastic plugs available which help enormously. These look like miniature
test-tubes in shape, maybe 1/2" long and are usually sold in boxes from the
same displays as the assorted cable clips. You fit them to the masonry by
drilling a narrow hole of sufficient depth then tapping in the plug. The
plug has a fine central hole which then takes the cable-clip's nail and
holds it securely.

--
Jeremy C B Nicoll - my opinions are my own.

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