Tensioners are used to tension 5" Rail. To tension the rail, simply insert 2 x 1/2" Long Handle ratchet Drives into the top and bottom of the Tensioner and rotate. Tensioners can tension up to 100 metres of Flex Rail. Tensioners are a permanent fixture of the fence and can be used anytime to re-tension the fence. Tensioners are Hot Dip Galvanised and Powder Coated for maximum longevity. PLEASE NOTE THAT THIS TYPE OF TENSIONER CAN CAUSE POST ROTATION ON ROUND POSTS. POST WEDGES MUST BE APPLED TO ROUND STRAINING POSTS TO PREVENT ROTATION.