Male/female (m/f) rod, speed rod M/f drill steel is an alternative to couplings sleeves to include the female part of the threaded connection as an integral part of the drill steel. M/f drill steel provides more rigid connections and is easier to uncouple and handle. The service life also tends to be better than with separate couplings. The advantages of drilling with m/f steel include: easy handling, quicker uncoupling, tighter connections, the potential to drill straighter holes, and longer service life. Extension rod size Mf-rod r32-round32-r32, length 3 4 5 6 10 12 14 ft Mf rod t38-round39-t38, length 4 5 6 10 12 14 ft Mf rod t45-round46-t45, length 5 6 10 12 14 20 ft Package: in wooden case or in bundles.