The round cross sections are more prevalent for extension drilling applications. A round rod has less material and thus is lighter to handle and less expensive than an equivalent size hexagonal rod. While hexagonal rod is particularly advantageous for drifting and tunneling drilling. The increased rigidity of hexagonal drill rods enables them to abating hole-deviation and enhances flushing for cleaning holes. Even with the larger cross section, hexagonal steel can still accommodate the same diameter bit as that of an equivalent round steel. M/f rods provides tighter connections and is easier for handling and quicker for uncoupling than m/m rods, and are potential to drill straighter holes. Carburization technique is mainly used in the production of big diameter rods to ensure excellent performance. Carburizing is for hardening entire rod to provide an external over entire rod surface area. Carburized steels are used primarily in underground applications and where water is used as a flushing medium. High frequency technique is primarily used in the production of small diameter rods to reduce fragileness of drill steels. High frequency is for hardening only the thread ends of the rod. This provides the longevity of the product as well as being more suitable for more drilling condition need. Steels produced with this technics primarily used in surface drilling applications where air is the primary flushing medium. Phosphorising is to improve anti-erosion capability of the entire external rod surface area. Product name: Extension mf drill rod Description: Thread drill rod made with best quality alloy steel bar, through heat treatment like atlas. Material: Alloy steel bar 23crni3moa Moq: No moq required for testing and trial order Body type Round shape and Thread type R32, r38, t38, t45, t51, t60 Diameter Hex25, hex28, rd32, rd38, rd45, rd51 Type Thread extention rod or m/f rod Length 600mm-6400mm