This is a very versatile set that allows you to weave in and out of the upright poles to mimic real-world sports movement patterns. The crossbar poles can also be used to duck under or jump over. The swiveling connector clips support multiple configurations, including diagonal pole formations. The possibilities are endless. The entire set is constructed of durable PVC plastic and can be used indoor or outdoor. Included are four dome bases that can be filled with sand or any weighted compound that will fit into the 1-inch hole. We found that for most applications, the bases do not have to be weighed down even in moderately windy conditions. In instances where the surface may be uneven such as grass, weighing the bases down helps keep the poles level.