Usually for extension rods, there are R22, R25, R28, R32, R38, T38, T45 ,T51,ST58, T60 threads, and different lengths of rods are available from 600mm to 6400mm usually.
(1)Steel grade: Male-Male Rod, MF Rod
(2) Thread: R22, R25, R28, R32, R38, T38, T45, T51,
(3) Rod size : hex.22mm, hex.25mm,hex.28mm, hex.32mm, hex.35mm, dia.39mm, dia.46mm. dia.52mm
(3)Length: 0.4m-6m
(4)Package: in wooden case or in bundles.
(5)Productivity: 20000MT / month E.G. R25 (1'') R28 (1 1/8'') R32 (1 1/4'') R/T38 (1 1/2'') T45 (1 3/4'') T51 (2'') T60 (2 3/8'') Drill bit R/T38 Extension rod T38 - Hex. 32 mm - T38 Extension rod T38 - Round 38 mm - T38 (Speedrod) Extension rod R38 - Round 38 mm - R38 Extension rod T38 - Round 38 mm - T38 Extenstion rod T38 - Round 38 mm - T38 (with double thread) Guide rod T38 - Round 45 mm - T38 (Speedrod) Guide tube T38 Coupling R/T 38 
