An essential consideration in the design of a telescopic cover is the traverse speed. Up to 15 m/min the covers do not need specific buffers, except in special cases. Between 15 and 30 m/min specific accessories are required to cushion the impact between the elements in order to make them last longer. From 30 to 60 m/min scissors are fixed on the cover. Thanks to their “concertina” movement, they prevent impact between the elements and allow them to move smoothly.