Made of heavy duty clear plastic that resists yellowing, fading, and cracking. Easy to Use: Simply insert the Fuelhawk until it touches the bottom of the tank. Then place your finger firmly over the top of the opening to lock fuel in the tube. Remove and instantly see how much usable fuel in U.S. gallons is inside the tank. The Fuelhawk is ideal for when the pilot must take a less than full fuel load due to weight considerations or measuring how much is really in the tank. Made In USA