Developed for tunneling applications, Rockmore International's new XT33 thread design for rod/bit connections has been engineered to provide increased thread life and optimal coupling/uncoupling function. The design incorporates a larger 33-mm thread diameter, a trapezoidal thread profile, a short-length thread interface and a rod/bit cylindrical contact zone. All are intended to work together to promote longer bit life, more effective energy transfer, higher bit-penetration rates, increased connection rigidity, higher precision collaring and straighter holes. Rockmore International