I bought what the man in the viola shop told me to...

But my mum said ti looked a lot better, so there you go! It has been an ongoing problem, because my first teacher was a direly incompetent man, who knackered up absolutely everything about the way I play the viola for me. My new teacher still sometimes asks me if my last teacher told me to do that...
But I digress! I just wondered, because I'd never actually seen them until lost of people seemed to somehow get them recently...