Large search disks increase depth amplitude by certain proportions. However, the point to know is that an extensive search coil while searching deeper cannot see many small things on the surface.
One of the most important points to consider is whether the detector is under warranty. It should be noted that in some detectors defects may occur as in any other electronic instruments. European Technology Group guarantees two years of service and spare parts for all detectors sold.
Detectors are similar but their techniques are different. Like all other goods, product features vary with price in the right ratio in detectors as well. Detector prices vary depending on their characteristics and the techniques it uses.