It is now capable of changing coils because now with this modification you can get a perfect Ground Balance, When changing coils from my collection of smaller coils the Ground Balance will be off somewhat from changing the coil. Some claim it made the IDX Pro deeper and that may be true because with the adjustable Ground Balance you can really dial it in. It is a fun detector when hunting a trashy area because it can be slow walked through the closely spaced targets and identify each non ferrous with the fast target response and spot on TID. I think I paid $100 back in 2007 for his modification and that included return shipping.

Randy