Remember KnowRoaming? That seemingly magical sticker SIM supposed to be attached on top of your usual one, so you can avoid expensive roaming charges? It's finally available for purchase. KnowRoaming works with a GSM Android, iPhone or Windows mobile device and connects you to a local carrier as soon as leave your home country (where it stays dormant) and enter another one. We first heard of it in 2013, when the startup was trying to raise money for production through a KickStarter campaign. It started shipping kits to its backers in February this year while it was still in beta, but after 12 months of testing, it's now ready for a wider release.