DETECHS NEW EXCELERATOR II - 18"DD COIL FOR THE GARRETT GTI2500 METAL DETECTORS GIVES THE GTI2500 MORE DEPTH !!! THIS COIL COMBINES BOTH CONCENTRIC COIL & 2/D WIDE-SCAN COIL IN ONE ! ITS BEEN 3 - YEARS IN DESIGN & TESTING INCREASE 20-30% THE DEPTH OF FINDING