(All CHILLrafts come with one tether plate on top; this would be extra one, added to bottom of chillraft unless noted differently on your order. This extra tether system includes a tether rope.)
Your CHILLraft already comes with a tether plate on one side (top). However, some people prefer to have a tether plate on the other side (bottom) to create less movement when the CHILLraft is anchored out on the water. Just remember to give it some slack to prevent too much tension on CHILLraft.