HI guys im in the market of upgrading from a garrett 350 to either at pro or gold, my opinion about the ace 350 great machine for the beginners out there, but back to my question COILS FOR GARRETT AT PRO AND AT GOLD, what types of coils are available and is there any available that'll detector 12 inches plus for deeper coins or relics, ive read on another forum about the nel type coils, has anyone tried these and do they work, any information would be muchly appreciated.