Saybolt Universal Seconds(SUS) is used to measure viscosity. The efflux time is Saybolt Universal Seconds required for 60 milliliters of a petroleum product to flow through the calibrated orifice of a Saybolt Universal viscometer, under carefully controlled temperature and as prescribed by test method ASTM D88. This method has largely been replaced by the kinematic viscosity method. Saybolt Universal Seconds is also called the SSU number(Seconds Saybolt Universal) or SSF number(Saybolt Seconds Furol).