This product appears in bulk. It is based on unsaturated polyester resin, reinforced by glass fiber, to which other fillers and additives such as hardener, lubricant and pigments are added. The final product achieves high mechanical strength and perfect electrical properties, especially the arc resistant and tracking resistant properties are unique compare to the traditional thermosetting plastics. The product has good molding property. It is an ideal substitute material to make isolating structure parts of low-voltage electrical appliance.