Initially the speed of sound apparatus was used independently. So far, data for several alcohols (Methanol, Ethanol, 1-Propanol, 1-Butanol, Cyclopentane, 2-Propanol, 2-Butanol, Isobutanol, 1,2-Propanediol, 1,3-Propanediol, Ethane-1,2-diol) were measured over the temperature range from (–20 to 80) °C at pressures up to 30 MPa. Moreover, sound speed was measured in Benzene and Heavy Water (D2O). Thereby the expanded (k = 2) uncertainty in speed of sound was estimated to be between (0.011 and 0.036)%. The speed of sound apparatus and the single-sinker densimeter were modified recently so that the speed of sound and the density of fluids and fliud mixtures can be measured simultaneously. Density measurements can be carried out over the temperature range form (–25 to 200) °C. Overall, measurements can be conducted at pressures up to 20 MPa.