PURPOSE: To improve resistance to corrosion, weather-proof, creepage resistance and shock resistance by making the stay with a molecule oriented forming made of polyolefin with ultrahigh molecular weight having a specific limit viscosity.

CONSTITUTION: The stay is made of a molecule oriented forming made of a polyolefin with ultrahigh molecular weight whose limit viscosity [η] is at least 4dl/g. Then as the polyolefin with ultrahigh molecular weight forming the molecule oriented forming, polyethylen with ultrahigh molecular weight, polypropylen with ultrahigh molecular weight, poly-1-butene with ultrahigh molecular weight or 2 kinds or over of α-polyolefin copolymer with ultrahigh molecular weight is used. Moreover, the molecule oriented forming made of the polyolefin with ultrahigh molecular weight is light in weight with high strength, and excellent water resistance and salt water resistance are obtained. Thus, the corrosion resistance, weather-proof, resistance to creepage and shock resistance are improved.