THIS IS A HEAVY DUTY HIGH QUALITY CUTTING TOOL BIT WITH 6 SETS OF NEW BLADES NEVER USED. THAT CAN BE EXPANDED TO CUT DIFFERENT SIZE CIRCLES IN METAL OR PLASTIC. THE SHOCK SLIDES UP INSIDE WHEN CUTTING. VERY WELL IMADE IIN GERMANY. IF ANYONE CAN PROVIDE ADDITIONAL INFORMATION ON THE FUNCTION, HOW IT WAS USED AND WHAT IT WAS MOUNTED ON IT WOULD BE APPRECIATED.