Portable device with very stable trolley The oxygen cylinder (usually with capacity of 5 or 10 liters) is attached in vertical position to the trolley. The trolley is very stable. The unit has a steel body and includes five castors with anti-static rubber. The trolley optionally includes a cover for the cylinder. Configuration of the complete device can be defined by the user to meet specific needs. The flow meter (0-15 l/min) can be used with a reusable or single-use humidifier, a resuscitator and the suction units for this model of portable oxygen-therapy device. The cylinder is fixed to the plate by quick-release connectors and the regulator can be disassembled without tools, allowing very quickly and simply to change empty cylinder with full one.