Very Very Small Maps of Hong Kong

KeyMap and CardMap How small can a map be and still be legible?, a spinoff of the Hong Kong-based Universal Publications Ltd., is publishing some very small maps indeed. Douglas Li of ZoomMap writes:

[W]e create and publish miniature maps — magnifiable up to 50× — of various areas in Hong Kong and China. When I say miniature, I mean tiny, on the scale of saying “a fistful of maps.” They are provided in two different sizes (KeyMap: 150mm × 230mm and CardMap: 235mm × 355mm), and go for about $25 and $35 Hong Kong Dollars, which converts to $3.3 and $4.6 CAD, respectively.
I believe they’re the smallest professional maps of its kind, as nobody else ever decided to make such small city maps before. They’re in full detail, which means that they contain all the information available on commonly larger maps. When folded, the KeyMap is about the size of a key, while the CardMap is about the size of most credit cards.
They come with a magnifying glass with 2.5× and 4× zoom, as well as a protective PVC cover to protect both the map and the magnifying glass.

Links added. The maps aren’t available overseas, but the concept is very interesting: the smaller a map physically is, the more likely you’ll take it with you. Whether it’s usable in practical terms is another question.