1[Premium Material] The lane line tightener is made of 304 stainless steel and ABS material, which is scratch resistant, corrosion resistant and durable. 2[S Hook Design] Stainless steel S hook of the tightener and stainless steel tightening shaft, the tightness of the pool lane line is controlled by the tightening shaft. 3[Easy To Use] Professional lane line tightener, the rope of the pool lane line can be fixed on the tightening shaft directly from the back hole, and the tightening can be adjusted. 4[Tensile] Swimming pool lane rope tensioner has high tensile strength, is not easy to be damaged, has strong buoyancy, is wear resistant and has a long service life. 5[Multi Application] Lane line tensioner is widely used in beaches, indoor and outdoor swimming pools, etc, small size, lightweight, easy to carry and use when going out.