It is basically like a travel card with photo ID on it and a magnetic strip.
You have to phone and book a black cab, I’ve never actually used it yet so I’m not too sure exactly how it works.
I know that my council allows me to double swipe the card on a single trip I think it’s then up to a max of £18 per trip.
Reading online there are mixed reviews of booked cabs not turning up? No good for me.