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.