I like the low profile of the F450. I wanted to put the battery on the bottom to keep the center of gravity low. To do this I needed to provide a little more space. So I added chopped off legs and stuck them in ping pong balls filled with construction foam. I had to be careful to keep the legs level as the foam set. I am very happy with the results. The platform is very stable and no sharp edges to catch on landing that might cause the quad to tip over and break a prop.