The Makro Racer is a good metal detector, but you shouldn’t hunt without a battery box cover on it. And it’s not only about digging in the mud. The speaker grill becomes clogged with dust from the dry ground as well. See the photos: not original cover for the Makro Racer.
For what the Makro Racer’s original cover looks like, see here. Personally I got it from the PRO package. I don’t know whether the standard package includes this one and how much it costs separately.