CONOSTAN® is the original source of D-Series Standards. More than 35 years ago, the U.S. Department of Defense’s Spectrometric Oil Analysis Program Standards Committee required standards for its wear metals analysis programs. With no reliable commercial source of metals in oil standards, the CONOSTAN® research team set to work in developing a reliable standard. The result was CONOSTAN®’s uniquely superior sulfonate chemistry which was adopted by the Department of Defense for its D-Series Standards.