... insulator Material: porcelian Type:1.SM-25Tensile strength(LBS): 500,Torgue Strength(FT LBS):6, Voltage withstand(KV):6,screw(mm):6 ... ):12,screw(mm):8,weight(G):865. SM-45Tensile strength(LBS): 1000 Tongue Strength (FTLBS):20, Voltage withstand(KV):15Screw (mm ... ):8,weight(G):706. SM-51Tensile strength(LBS): 1000, Tongue Strength(FT LBS):20, Voltage withstand(KV):15Screw (mm):8, weight ...