Horizontal Hole openers, also known as HDD reamer, are used to enlarge the diameter of a pre-drilled hole. They are custom built to specification, and come in a wide variety of sizes. HDD is used when trenching and excavating is not practical. This drilling technology allows for a steerable trenchless way to drill underground. There are three stages, the first stage is to drill a small diameter pilot hole. The second stage is enlarge the hole with a larger diameter cutting tool called an HDD Reamer, Rock Reamer or Hole Opener. The third stage is inserting the casing pipe or other product into the enlarged hole. Features: 1. The product is used for the reaming of the oil, gas, petrochemical, sewage, power and fiber optic pipelines in the no-dig horizontal directional drilling. 2. Directional crossing operation is widely used in unexcavated project. 3. Small torque force can be applied to hole opening with drilling machine. 4. Hole opener includes body and the cutter. 4 different types of cutter can be assembled to the body in one size for opening the hole in 4 sizes. 5. Cutter can be divided into MT type used in soft formation and TCI type used in hard formation.