afaik, these carts are only made for the 801/penstyle. I've looked at a lot of sites, and I've never seen them for the 510.
I'd love them for the 510 too, but I don't think they exist at the moment. If it's any consolation, people say that there is a rubber taste to them that's hard to get rid of, so maybe it's better not to have them. If you're really sold on the idea, some
tobacco shops are reported to have little rubberized sleeves that you can use with a normal cart.
Hope this helps