This Saudi standard specifies requirements for five basic series of glass hydrometers of constant mass which are graduated to indicate density (kg/m3 or g/ml) at 20oC. Each series comprises hydrometers which between them cover the interval 600 to 2000 kg/m3 or 0.6 to 2.0 g/ml. The hydrometers are graduated appropriately for use in liquids of low, medium or high surface tension. It also specifies three sub-series of hydrometers which are graduated to indicate density at either 20oC or 15oC. These hydrometers have smaller tolerances on scale error, are limited to the range 600 to 1100 kg/m3 or 0.6 to 1.1 g/ml and are for use in liquids of low surface tension. This standard does not cover hydrometers with a built-in thermometer. A table of standard categories of surface tension is given in annex A. A table of recommended stem diameters is given, for guidance in manufacture, in annex B. Part 2 of this standard deals with test methods and use of density hydrometers.