1945 MICRO S MERCURY DIMES

I CANNOT SEEM TO TELL THE DIFFERENCE BETWEEN A REGULAR 1945S MERC DIME, AND A MICRO S VERSION. I HAVE LOOKED AT ALOT OF PICS OF BOTH, AND THEY LOOK THE SAME TO ME. CAN ANYONE OUT THERE TELL ME HOW TO TELL THE DIFF? I HAVE BEEN TOLD THAT THE 'S' IS SMALLER ON A MICRO, BUT I HAVE SEEN NGC GRADED ONES, AND THEY LOOK LIKE THE REGULAR S TO ME. I HAVE ALSO HEARD THAT THE MICRO S'S HAVE TWO 'S' MINT MARKS. HAVENT SEEN AN EXAMPLE YET. HELP, PLEASE.