The Series TLI Tank Level Indicator provides a visual indication of the height of liquid contained in a tank. The 1/2-foot unit can also be used as a sight flow tube when mounting in a pipeline. The TLI series utilizes a double wall construction to indicate the level of corrosive or ultra-pure liquids and is available with PVC, Polypropylene, or PTFE fittings and 1/2" or 3/4" NPT threads. Fluoroelastomer seals are standard.