BT100M/DG(6), flowrate range is 0.002ml/min-36.6ml/min. Flow and speed can be adjusted either by digital rotary knob, instead of the traditional way of membrane keypad, which reduces the failure rateobviously; or by automatic control through the external controller interface, with three available modes: 0-5V, 0-10V and 4-20mA. Memory function is also available in case of power off.Besides, rotary knobs are designed clearly so that it is easy to operate for customers. FULL SPEED button is available to fill in & empty out quickly. Not suitable when used in the open air.