Hyaluronic Acid polymers (bacterial origin), low in endotoxin, suitable for molecular weight calibration and in applications that require polymers with well-defined molecular weights and low polydispersity. The molecular weight parameters have been calculated by an absolute method using Triple Detector Analysis (TDA), light scattering, viscometry and UV. The products cover the range from 93,000 to 1,100,000 daltons (93kDa to 1,100kDa).