The Accu-Level Removable Propane Tank Gauge utilizes a very special yellow ink. When slightly heated, this ink will change color from yellow to orange. Upon cooling, it will change back to yellow, There is nothing that gets used up or wears out.

Easy to Use: Attach this Propane Tank Gauge on the side of your 20lb tank. Pour a cup of hot water down the Propane Tank Gauge. Immediately the entire Gauge will turn orange. However within a few seconds, the lower portion will return to yellow. This returned yellow color is below the surface of your propane. The gauge holds this activated color for about 30 seconds.

Features:

• Fits RV and BBQ tanks
• Visually shows level of gas
• Easy to Use. Last for years. Will not fade in sunlight
• Activates with a cup of Hot Water poured over the strip