Soft and great for Bat-Sleeping, the 60% cotton 40% polyester Batgirl Ribbed Women's Tank & Panty Set will allow you to hang from ceilings and use echolocation to find insect prey! Oh, that's a different kind of bat-sleeping. This will just allow you to lounge about the house and proudly display the black and yellow symbol from Batman and Batgirl! The Batgirl Ribbed Women's Tank & Panty Set - it's not for hanging upside down.