4 large, heavy-duty cork-screw anchors twist into the ground. A sturdy strap secures to each anchor & attaches to the frame of the trampoline. When properly installed, the trampoline will be divided into 4 equal sections to evenly distribute the tension & safely secure your trampoline & enclosure (if installed) to the ground. Helps prevent strong winds from moving/flipping your trampoline. This anchor kit fits perfectly with all 12ft, 13ft, 14ft & 15ft trampolines.