THE SHAFT IN THIS KIT DOES NOT HAVE A 1/4 OR 1/8 TAIL. WILL NOT FIT MY RYOBI ROUTER OR MY FLEXIBLE ROUTER HAND TOOL. Also, I'd like to add that I've tried using them with a drill, but it's not worth trying. USED ON A PIECE OF WHITE PINE AND WILL NOT BE CUT OUT, ALL YOU WILL DO IS MARK YOUR WORK! I WILL NOT EVEN GIVE HIM 1 STAR. SORRY TO LEAVE 1 STAR JUST TO LEAVE MY RATING