SEARCHING FOR - NOT FOR SALE

Searching for this Lululemon all your seawheeze crew- fleece . Have previously owned an eight recently bought one online from someone that they thought was a six (18 inches pit to pit) the size 8 is 21 inches pit to pit. The one I bought, unfortunately is definitely a size 4, I’m looking for a size 6 so somewhere between the 18 inches and 21 inches would be a size 6.