This coil has been tested and works great.
Description: Waterproof DD Search Coil
Size: 28cm / 11"
Including coil cover and coil mounting hardware.
Most of these items are Amazon/eBay returns.
Ie: They got it as a gift and didn't want it. Buyer remorse. Had a change of thought and decided to take up basket weaving. Who knows?
This means most of them have never even seen dirt.