It is constructed of light and durable aluminum alloy consisting of 3 sections each with a reliable polycarbonate button lock. Graduations are anodized with special weather resistant and corrosion resistant inks to withstand the harshest work environments. Tight tolerances on the extruded aluminum sections allow for smooth extension and prevents any sloppiness or clattering. A convenient measuring scale exists on the backside premit users to read height of rod at eye level. The level rod base is reinforced with an extra plate of aluminum and each section collar is constructed from impact-resistant plastic and riveted for added durability.Northwest laser auto level transit tripod rod ftins tripods & grade rods click here ups transit map. (contact me for additional information). Nat91 tripod & nar09e ft/in’s grade rod combo.