Senso4s Basic Gas Cylinder Level Indicator - Bluetooth The Senso4s Basic Gas Cylinder Level Indicator is an absolute game-changer when it comes to keeping on top of your LPG cylinders. You can now keep tabs on your gas levels using your smartphone, no more wondering when you're going to run out. This thing is designed for everyday use - be it for home cooking, camping, or even caravanning, it's handy to have around. Using Bluetooth and the Senso4s mobile app (which is free on iOS & Android), the Senso4s Basic will give you a real time read out of your gas consumption. You can even get a forecast of when you're likely to run out, and see how your battery is doing all at the same time. Just pop the Senso4s Basic under your gas bottle and let it do the rest. It fits most of the common gas bottle sizes out th