The PrO-E-M education laboratory centrifuge is designed to work with low-speed large volume rotors. Included is a swing out rotor type BRK5508L available with 8 positions, designed to handle 50 ml tubes. Separately, you can purchase the following fixed angle rotors: BRK5431 - for 24 x 15 ml tubes and BRK5434 - for 8 x 50ml tubes and also the swing out rotor BRK5510 for 4 x 250 ml containers. The centrifuge has four modes of operation at different preset ro7tor speeds. There are 4 LEDs on the front of the centrifuge showing the current operating mode. A beep sounds after the end of the program announces that the rotor has stopped.