The R73 Series is constructed of polypropylene film and metal foil or metallized film and metal foil with radial leads of tinned wire. The radial leads are electrically welded to the metal layer on the ends of the capacitor winding. The capacitor is encapsulated in a self-extinguishing solvent resistant plastic case with thermosetting resin material meeting the UL 94V–0 requirements. Two different winding constructions are used depending on voltage parameters.