the present invention has two metal wires 10 and 12 in the present embodiment 0 100 inch diameter steel wire 121 2 gauge is used having a tensile strength of approximately 250 000 pounds per square inch it will be understood however that any wire having suitable characteristics may be used wires 10 and 12 are ensheathed in a plastic casing 14 plastic casing 14 preferably has a thickness between 30 and 100 mils in the gap between wires in the preferred embodiment its thickness in the gap is approximately 0 050 inches and its thickness about wires 10 and 12 is such that the outside diameter of wire and sheath is approximately 0 200 inches the vertical width of wires 10 and 12 and casing 14 is approximately 2 5 inches in the presently preferred embodiment casing 14 is composed to polyvinylchloride although it will be understood that any suitable material may be used casing 14 containing wires 10 and 12 is secured to a support 16 by means of a securing staple 18 support 16 is typically a wood or concrete post securing staple 18 may be made of galvanized steel and is deformed to follow the contour of plastic case 14 securing staple 18 has four fasteners 20 22 24 and 26 fasteners 20 and 26 are attached to tongues 21 and 27 respectively and pierce support 16 respectively above and below casing 14 fasteners 22 and 24 pierce casing 14 before entering support 16 as can be seen best in fig2 securing staple 18 presses against casing 14 securing casing 14 firmly in place fig3 again shows wires 10 and 12 contained in casing 14 in fig3 a.