A rubber test specimen is contained in a die cavity that
is closed and maintained at an elevated temperature. The cavity
is formed by two dies, one of which is oscillated through a
rotary amplitude. This action produces a sinusoidal torsional
strain in the test specimen resulting in a sinusoidal torque,
which measures a viscoelastic quality of the test specimen. The
test specimen can be either a raw natural or synthetic rubber or
an uncured rubber compound