This is natural when the wind pushes and pulls the bars to become loose in their anchor points. In turn, this doesn't allow your windbreak to sag, so you can truly put up your feet and relax. Using the adjustable screw, you can set the specific length between the bars, this then creates a solid structure to prevent each bar from moving.Reliable delivery.Specification:Diameter of Main Pole: 25MMDiameter of Secondary Pole: 20MMOverall Length: 50CM - 100CMMax Bar Diameter Compatible: 21MMWindbreak StretchersWhen using windbreaks, it tends to all go well for the first ten minuets, however, after that the fabric between each bar tends to sag. With the bar horizontal simply place a vertical bar holding your Windbreak up into each end.The simple solution to this common issue is the Windbreak Tension Rod. Each end has open slots that a bar can rest into.International delivery.