For polypropylene, high density polyethylene and other high temperature thermoplastics, 5/32" round rod when used with any of the 40s Series and FUSION Series welders. Applications for the KS-1C tip include the following: Electrical and computer enclosures; Plastic piping tanks and systems; Chemical processing and waste treatment equipment; Wet benches and processing stations; Laminar flow benches; Silicon wafer cleaning equipment; Wave soldering, photo processing and laboratory equipment; Etching stations; Orthopedic and prosthetics and Plating tanks and barrels.