An accessories for assembly type diamond core bit. Tubes can connect with each other for extra lengths, therefore, we can apply them for drilling deep holes.

• We can add more tubes to increase the drilling depth.

• Adding one more tube (300 mm) will increase 270 mm drilling in depth.

• Excellent concentricity to ensure trouble-free drilling operation.

• When the segment is used-up, you only need to replace the crown bit. The tube and the coupling can be reused for many times.