FPP Meters (Tuthill / Fill-Rite) TS Series "Stealth" Positive Displacement Flow Meter. FPP Meters Stealth series liquid flow meter, designed for measuring gallons in industrial applications.It features a mechanical register with a 5-digit display and a prominent "Do Not Reset While Counting" warning label.The unit is manufactured by Tuthill Transfer Systems.These types of meters are commonly used for high-volume custody transfer applications, such as fuel dispensing.