With 'Cylinder Gas Level Magnetic Indicator' you will never run out of gas from now on. Measure your gas with this level indicator, simply attach it to your gas tank cylinder with this magnetic Gas Level Indicator and it will show you how much gas is left in your tank. • Features: This product can safely and accurately measure the gas capacity, according to the gas temperature evaluation, measuring the temperature range of -10 C~ 120 C. Will actually show you when you are low on gas, before you run out! Works while you are using the BBQ Save money by using more gas from each cylinder Safe & accurate Reusable Works on LPG (propane) & cylinders Magnetic backing allows for easy reuse on exchange bottles Comes with instruction • Instructions: 1.Place your Gas Level Indicator on a clean area on the lower half of the cylinder. 2.Turn on the gas and wait 10 minutes before you can read your Indicator. 3.In the winter the bar on the left will be active, and in the summer the bar on the right will be active. 

•Working principle: 

The temperature of the upper gas is high, and the temperature of the lower gas is low. Depending on the color segmentation of the product, the position of the boundary line is where the gas is located.

When examining the product, examine. It with the gas bottle open and examine it while using it.Because this product is used to ascertain whether the gas is used up or not, the product is attached to the bottom of the bottle and can only be measured when the gas is  running out.If the gas is above the evaluation card, the assessment result is wrong, the buyer can put a few sheets of the product on the gas bottle.Material: Material: PET Plastic+ Liquid Crystal + Soft Magnetic • Color: multicolour• Size: 10*6.2cm*0.1cm/3.94"*2.44"*0.04" • Note: 1.Please allow 1-3mm error due to manual measurement. Please make sure you do not mind before you bid.