The w-o-w is essentially a flexible vinyl cylinder about 18" in diameter and 24" tall. It's built with 2" diameter "pockets" running from top to bottom all around it. When you place the cylinder on the ground (around your plant) and fill all the pockets with water (easier w 2 people), the cylinder more or less defaults into the shape of a teepee. It's self-supporting, but the hole at the top tends to be fairly small (2-4") unless you put some stakes inside to keep it open more. The weather forecast determines how wide you want that top hole to be. If your plant grows out the top before the weather becomes safe for the plant, you have to make other arrangements if you want to protect the top.
The initial value I recorded for my zone was wrong. Per the USDA map, we're in 8a, too. I've fixed it.
