I personally don't hunt with coil covers anymore. That was my decision regarding coil covers. I have two different machines, two different brands. I own every coil available from the manufacturer of each. They are each mounted on their separate lower rods for a simple, quick switch. Unless you seal those covers to the coil watertight, and I mean guaranteed watertight...you could be in for a surprise when you least expect it. My coils were sealed and I was extremely confident they would remain so. One little pinhole in the sealer is all that is needed. A little dust, a little dirt, a little water all mixed together between the coil and cover can make for a frustrating day of hunting. I know, it happened to me. I have no use for covers now. I'd rather have a quiet machine than the possibility missing a gold a ring with a noisy one. Haven't ruined a coil yet. Read up in your Owners Manual about the maintenance that is recommended. Periodically remove this, remove that. Clean here, clean there. It is not an easy job to remove that sealer for cleaning purposes. It's a choice. Metal detectors are not maintenance free. I do not hunt in the boulders, or in rocks nor prospect for gold nuggets. Perhaps then, perhaps. HH