You stick them on using nail glue and should last for up to a week. I've had mine on for 2 days now and they shows no signs they're about to ping off, I just hope that when they do I am aware of it so I can reuse them!
The leather effect polish goes on like a standard polish, but when it dries, turns to the effect of leather. Last week I went to the QVC press day, and had it tried on there. This is Shoreditch Lane, a mulberry shade which will be coming out next March alongside a tan colour (Soho Mews) and black (Noho).
I wasn't too sure about these when I had them done - they reminded me of nails that I had accidentally touched when tacky... however they did grow on me - particularly when I saw the black being worn at Tuesday's event. I think because it looked much more leather-like. I will definitely be picking up one of those when they hit stores.
The sets out next month are the black polish, Noho which comes with silver skulls, or the tan polish Soho Mews which comes with gold skulls. There is already a waiting list, so if these tickle your fancy, get your name on it here!