Level Check is a mobile filling level indicator for all (propane / butane - LPG) steel or aluminium gas cylinders with a diameter of 200 to 350mm. The device recognises whether there is liquefied gas in the cylinder at the measuring point and indicates this.
This is a brillaint product from truma, simple and acurate device. 
Small and easy to store -keep in the glovebox or cuboard and always on hand to check how much gas you have left in your cylinder