The Appetito Magnetic Gas Level Indicator shows you when you're running low on gas, before you run out! This handy tool is reusable and works automatically, while you grill. Suitable for any LPG Gas tank, this nifty device works by measuring the tank's temperature to accurately indicate the remaining gas level. It's the must have item for any keen BBQ griller or camper. To use: 1.APPLY THE INDICATOR: Place the indicator near the bottom of the tank below the middle weld line, out of direct sunlight. 2. TURN ON THE GAS: This indicator only works when gas in on. 3. WAIT 2-5 MINUTES 4. READ THE LEVEL a. When the tank is FULL the gas level is above the indicator and no level will be shown. b. When the gas level falls within the range of the indicator, the colour will change in at least one of the bars shown to the right. c. If more than one bar changes, level is shown where the left most bar is indicating. 5. WH Automatic function. Suitable for any LPG Gas tank. NOTE: Extreme temperatures below freezing or above 38C may affect the accuracy of this indicator.