●Magnetic Base Top tapped with metric M8 x1.25 threaded hole ●Indicator Holder with super strong magnet with 250 pounds of holding power,The thickness of the adsorption site is greater than 3cm ●Magnet base has an On/Off switch which easily and quickly engages ,releases magnet ●The dimensions of the magnetic base are 4.72x1.96x2.16 inch(LxWxH) ●Please attach the iron block to the 3CM thickness of the iron block in order to play its maximum power