The PLI Digital Portable Liquid Level gauge is designed to offer a simple, accurate, rapid and reliable method of determining the liquid level of high or low-pressure CO2, Halon, FM200, Propane and any liquefied gas under pressure, without the need to move or weigh the cylinders. There is no reduction in health and safety, and the risk of gas leaks during servicing is eliminated as cylinders remain active and in situ. The PLI Digital can be used on cylinders, pipe-work and any single skinned holding vessel with up to 25mm thick walls. It will also indicate the level of oil or water in a container or tank. The PLI Digital gives accurate results by generating an ultrasonic sound wave that travels through the container and into the liquefied gas or fluid. The pulse responds differently to the presence or absence of liquid, indicating the level of the liquid. The PLI Digital has the ability to boost the power by 12, enabling cylinders to be read even when they are in poor condition, or suffering from a layer of rust. The PLI Digital also has an inbuilt thermometer (in both C & F), an easy-to-read digital display, one-button set-up function for faster cylinder testing and smart plug, which enables the signal strength to be monitored by an audio signal from an internal speaker.