is a method for determining the viscosity of petroleum products; it is widely used in Europe, but has limited use in the U.S. The method is similar to Saybolt Universal viscosity; viscosity values are reported as "Redwood seconds."  Testing consists of either Universal or Admiralty.

UNIVERSAL is measured time in seconds required for 200 ml of fluid to flow through a measured tapered orifice 10mm discharge tube an 1.62 mm diameter and reported in seconds.

ADMIRALTY is essentially the same principle as Universal except has a longer length and larger diameter tube.

Other methods include Kinematic viscosity (ASTM-D-445),  Engler viscosity, Saybolt Furol and Saybolt Universal Seconds (SUS).