Garrett AT Pro Metal Detector Waterproof to 10 ft, 15 kHz waterproof coils Consideration 8 inch coil 10 inch coil S FF ASTRO MAX BLUE Consideration 8 inch coil 10 inch coil (this page) Ground coverage Less per sweep More per sweep Depth on open ground Good Slightly deeper Maneuverability in trash Better separation Bulkier in tight trash Best for Trashier sites The DD FC technology maintains pulse induction depth advantage while tightening the detection field The AT Pro's 40 level iron discrimination plus proportional Pro Audio lets us hear the size and depth of a target through tone It remains one of the most respected upgrade detectors in the Garrett AT Pro range