Why use a coil cover at all?
Just one more thing between you and the target and a source of problems.
Has anyone ever actually worn out a coil by scuffing it on the ground?
Most people I see using detectors are waving them about 6 inches off the ground as the swing madly along.
I have seen very few actually maintaining a close and proper distance thru their entire swing.
Which is a good thing ... leaves more deep targets for me ...
Even if you do wear out a coil in say, 5 years ... they are cheap and easy to replace.
Coil covers Indeed! Just one more gimmick item to sell you.