The product description：We should try our best to choose the drill rods which have many advantages such as proper section, lighter weight, shorter length, good rigidity and long life with meeting the requirements of drill hole. For rock drilling with drill rod in person’s hands, H22 and H25 drill rods should be chose which are hexagonal drill rods with taped connection, and the size of the tail of drill rod is 108mmxH22, the material is 55SiMnMn, 95CrMo.etc; For rock drilling of drifting, we choose the drill rods such as the drill rods with hexagonal cross section,threaded connection and same-diameter, the drill rods with hexagonal cross section,threaded connection and different-diameter and quick-change drill rods (H25,H28、H32,H35) generally. For rock drilling for production (underground mining and strip mining), we choose the drill rods such as the drill rods with circular cross section,threaded connection and same-diameter, the drill rods with circular cross section,threaded connection and different-diameter and quick-change drill rods (D35,D38 ,D45、D51、D60、D65、D76、D87) generally. Matters needing attention1.Properly choose the appropriate drill rod per the testing comparison or the product recommendation of our company.2.Please make sure that the drill rod is well fit with the bit (uniform tamper); if the taper of drill rod is less than that of the bit, the top-point will be easily broken. 3.It is recommended to use the bill rod sets for place where the depth of rock drilling hole is more than 2.0m. That means firstly open the pore with a short bill rod and then continue to punching with a long drill rod to extend the working life of drill rod (based on different depth of the rock drilling hole, two or three drill rod sets could be used) 4.Please keep in a stable condition while opening pore and accordingly reduce the pushing air volume, the bill rod is not permitted working under bending-stressed condition, otherwise, the working life of bill rod will be shortened.  5.During the process of punching and the related withdrawal operation, please try to protect the bill rod from bending-stressed to improve the working life of the drill rod.6.Please adjust the air volume of rock drilling machine per the on-spot condition (rock condition) to guarantee the normal drilling operation.7.For rocks that cause the bill rod stuck, please use the cross-shaped bill bit.8.Users can not change the structure of drill rod at their option or reuse it after drill rod re-machined in case of affecting the normal working life of the drill rod.9.Please replace the regular drill rod with superior drill rod if the regular drill rods are massively fractured in early stage while working in normal condition; if there is no superior drill rod, please replace with the large-size drill rod, or reduce the wind pressure.  10.Diameter of the drill rod should properly match with power of the rock drilling machine, if the power is high, please choose the large-size drill rod.