An ultracentrifuge that can reach at least at least 60,000 rpm in which speed can be modified in 100 rpm increments and with an approx. maximum of at least 200,000 x g. It must have a vacuum control system, timer and temperature control (minimum range 4°C to 30°C). It should be provided with a compatible fixed-angle rotor for 12.5 mL tubes or similar, that can be used at maximum speeds of at least 70,000 rpm as well as the corresponding l tubes. The ultracentrifuge should be compatible with rotors from different manufacturers. Ideally it would also be supplied with an additional rotor such as a swinging bucket rotor, maximum speed of at least 40,000 rpm with an approx. maximum of 200,000 x g and corresponding l tubes