The Makita 8' Flexible Shaft Assembly, 1-1/2" Head Diameter (1910C4-5), is for use with the 40V max XGT® Brushless 5-1/2' Concrete Vibrator (GRV01), and the 40V max XGT® Brushless 8' Concrete Vibrator (GRV02). The 8’ shaft assembly features a 1-1/2” inch head that gives the user more options as the diameter of the head determines the amount of material that can be affected. Effective air bubble removal range is around 9" or approximately 10x the diameter of the vibrating head. The 1910C4-5 installs quickly and easily for added user convenience.