Thank you for viewing! (ᴗˬᴗ) I've worn this about 2 or 3 times. There's a zipper in the back, and a hook at the very top. However, I think it's the color of the zipper, but it's become a little yellowed. The fabric is thin, but it has a lining inside, so I don't think your underwear will show through. I usually wear a size M, and this fits me perfectly. Since this is a summer item, please refrain from purchasing if you are concerned about sweat, etc.