These base pieces seem to hold the umbrella in place, but there hasn't been a big wind to test them out. My deck is small and the umbrella and base take up more space than I'd estimated; not a product complaint, just me not looking carefully at the product details.
Easy to install, even without instructions. I filled with water, aligned with the legs, and locked them in place. Water has enough weight for Nevada high desert wind.
Love these weighted stands. They work really well with our umbrellas, they are not going to hold your umbrellas down all the time if it’s too wi day- we have had them fall over a couple times, but they are easy to put back together.
This base is very sturdy once filled with water or sand. It can be windy where we live and while the umbrella may move around a bit, the base is very sturdy and there are no worries about the umbrella falling. The pieces latch together easily with the provided hooks. Assembly is quick and easy. Highly recommend!