Air tested the umax coil on my Cortes and the High Output coil on my Vaquero. The High Output coil on the Vaquero is a whole lot more sensitive to small coins and rings. The High Output air tested a thin gold wedding band at 7 inches and the umax at 5.5 inches, both still giving a decent signal. But with those depths, pinpointing with the tips of the coil doesn't work, the signal is not from tip to tip anymore.