The monofilament tightener for sale are used to easily tighten our fencing monofilament wires in both 8ga and 12ga for the best looking and most effective installation possible. By inserting a length of monofilament wire into the groove of the tightener, the line may be tightened by slowing rotating the tightener with the tightener tool and shortening the line. The monofilament tightener is ultra-violet (UV) treated for increased longevity. We recommend using two monofilament tighteners between each corner of your fencing installation project - one each for the top and bottom monofilament wires. You will need our monofilament tightener tool to properly operate these monofilament tighteners.