The plastic base when filled is very stable.  The item does not come with any instructions or packing list.  It is great if you do not want to move it.  The wheels on it are not very useful.  You have to rock, pull tip the entire umbrella toward you and essentially dump the base and umbrella on its side to get the rig up on the wheels.  The base is about 225 lbs and the umbrella is about 75 lbs so its a lot of effort and work to " Roll It Around".  I would call it cumbersome at best.  It was not as I envisioned at all.