1. The drill rods comply with the provisions of API SPEC 5D & API SPEC7. 2. The grade of steel are determined according to the requirements of Group 1 & Group 3 of API SPEC 5D. 3. Drill pipe joints at the same level comply with the provisions under the Standard API SPEC 7. 4. Standard pipe size range: 2-3/8â??~6-5/8â?? 5. Hardbanding: The wear rate is less than 6% of that of bare tool joint, which can prolong 3 times of the tool joint service life. Good property of friction-reduction, which can reduce the casing wear to the least, and its wear to casing is less than 11% of that of bare tool joint. Reduce the torque of drilling string. 6. Widely used for oil, gas, water well and geothermal fields in Turkey, Poland, Japan, Singapore etc.