This coil is the most popular of the range due to its extra coverage and depth on small and large targets in a range of soil conditions.
If you're looking for the ultimate GPX series coil for good depth and sensitivity to shallow small targets this is the coil! When running the GPX 4500 as a full time prospector getting access to this coil for me was a game chjanger, i went from 2-3 pieces per session to squeezing out that 5-10 bits per trip and am confident the sharpness of target response this coil provides was the reason.