Trampolines sited in an exposed, windy area or with a safety enclosure fitted, have been known to take off. The tie down kit includes 4 metal anchors, which screw into the ground and webbing straps which attach to the trampoline frame. Straps are easily detachable from the anchors allowing you to move the trampoline to cut the grass.
If your trampoline is extremely exposed and is likely to be in an area of high winds, then we would recommend buying more than one kit.
One kit will secure four points of the trampoline, so if you want to secure each leg more than once, or have more than four legs on your trampoline you may need to look at the larger kit.