Lululemon Outrun 1/2 Zip

Lululemon 1/2 zip for running. White. I bought it a few years ago so I am unsure as to its correct sizing. I believe it is a size 6, as it is a little loose on me and I am normally a 4. There is a slight pull of the threads on the back right side. *Model photo is for reference on how it looks on only - it is not the exact product*