1, Premium Quality 2, M12 connection 3,4800RPM finger bit tipThe head finger bits for radial arm machines such as Wizard are guaranteed to last longer.For Thibaut, Wizard & other Radial Arm Polishers Size is 20mm(OD) x 20mm (H) x 12mm thread Soft Bond for hard granite Black/Blue color Diamond Head Finger Tips/ Finger Bit Tip