Rihanna in London

I am watching Rihanna's live concert at the Nokia Theater in London and loving it. I love her music and her style. She just wore the coolest accessory. It was an arm sleeve but the top of it had a puffy drapery look. It looked like it was made of leather (maybe). I've never seen something like that before but I would expect nothing less from the fashion forward trend setter. I tracked down a video where she is wearing the sleeve during her performance of Russian Roulette. Check it out here!