Search coils come in a variety of sizes and shapes. Generally, the detector you buy has been set up with a standard, all purpose coil.
You can benefit from changing that one out to a smaller diameter coil with more pinpointing capability, or a larger one to cover more ground.
There are even differences in coil design, such as the standard loop coil and the well known “Double D” coil. These variants help you adapt to the location you’re hunting in as well as provide helpful differences in the coil’s transmitted signal!
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