Klein's wrought iron pins with lead threads

Insulator Pins. — The pins made of wrought iron by John M. Klein & Co., of San Francisco, for electric light and railway line work have a lead screw cast upon the iron body. The screw, being lead, prevents the breaking of insulators from expansion or contraction. The stem of the pin, being wrought iron, will not decay and break, allowing the wire attached to fall in the street.