A bottom stop prevents the electrode from sinking down more than desired into the material during the welding cycle. The bottom stop can be used with almost all types of electrodes. This device is more or less necessary when welding non-woven materials. This is because a non-woven material is less persistent to pressure than a woven material when it melts, and if normal pressure is applied, there is a great risk that the electrode sinks right through the material during the welding cycle. This creates both a weaker weld and a risk for circuit flashes. Using an electrode with bottom stop helps creating a stronger weld. The bottom stop is very popular among pool liner manufacturers.