Yeah - I always thought it was like heat-shrink tube a bit... but I've seen a few types now and they all just seem like "book contact".... they DO stretch - and this is helpful to work out creases etc because it's a bit forgiving, but you wouldn't say, be able to wrap a mirror I don't think.... I've only done a few vinyl jobs, not an expert, it's possibly I don't know what I'm talking about
But from my experience, I'd forget about doing a front V lip (maybe a C lip like mine) in vinyl.... it'd be an abortion...