This roll of black steel wire 2000 feet long can be used for many jobs. The braided wire is thick (12.5 gauge), strong (breaking strength 1,200 pounds), and flexible. It comes with a black vinyl coating that protects it and gives it low visibility.
We use it for supporting the tops of deer fences and securing earth anchors to fence posts. In fact, however, it is a general purpose wire well-suited to a myriad indoor and outdoor tasks.
To use it as a top support wire for a deer fence, you need a way of securing the wire at both ends of a run. You can do this with a small u-bolt, passing the wire through the u-bolt, passing it around your chosen anchor post, and passing it back through the u-bolt in the other direction.
Then tighten the u-bolt at the top of the post so that the this braided steel wire cannot move in the u-bolt, and unwind the wire along your chosen run of posts until you come to the anchor post at the other end of the run. Cut the wire and do the same thing there, only before tightening the u-bolt, pull the wire taut (at the top of the post) so that it provides the necessary top support without being so tight as to tilt your posts.
Next, if you are setting up this top support wire with our round 1-5/8-inch or 2.5-inch posts, attach a brace band to the top of each post with its flanges pointed outward toward the deer. Then hang the wire from the brace band by placing a zip-lock tie under the bolt in the brace band and around the wire (and also around the top of the fencing if your deer fencing is present), and drawing the zip-tie tight. Finally, when installing the fencing, attach the top support wire to the top of the fencing with a hog ringer and staples, using about one staple per foot of fence.