I HAVE A 3-1/4” CARBIDE TIPPED CORE DRILL BIT. IT WILL FIT A 1-1/2” HAMMER DRILL. IT HAS A 1/2” CARBIDE DRILL BIT IN THE CENTER FOR STARTING YOUR HOLE IN THE RIGHT PLACE IN YOUR CONCRETE. I HAVE ONLY DRILLED TWO HOLES WITH IT. THE CARBIDE TIPS HAVE VERY LITTLE WEAR ON THEM. ITS 21” OVERALL LENGTH. THE END THAT GOES IN YOUR HAMMER DRILL IS SPLINED. MESSAGE ME IF YOU HAVE ANY QUESTIONS.