View product detail page of 1-3 / 8 In. x 21 In. Spline Speed-X™ Rotary Hammer Bit. 1-3 / 8 In. x 21 In. Spline Speed-X™ Rotary Hammer Bit 1-3 / 8 In. x 21 In. Spline Speed-X™ Rotary Hammer Bit Code: HC4081