The 12 gauge monofilament wire is used to strengthen our deer fence and to keep the fences from sagging between posts. We recommend installing a run of monofilament wire at the top and bottom of your deer fencing for best results. The monofilament wire should be crimped using our connection sleeves at each corner, end or gate system. Use our round monofilament tighteners and monofilament tightening tool to achieve your desired tension. The monofilament wire is ultra violet (UV) stabilized to prevent breakdown caused by the sun and weather.