The Coolaroo Turnbuckles helps to keep the shade sail connected. One turnbuckle connects from the corner ring to the fixing point. The other connects from the central ring to the same fixing point. When you have achieved the tension you need in your shade sail, lock both turnbuckles with a winged bolt and washer. Provides adjustable tension on the shade sail| Marine grade 316 stainless steel| attaches the shade sail to a fixing point| Use to connect shade sail corner ring to fixing point| Turn to apply necessary tension to the shade sail| There should always be two tensioning devices per shade sail