The Deluxe 10" cAntenna is more suited for long range coverage and high gain. What this means is the 10" cAntenna has a narrow 'beam' for pin pointing signals. Etherdesigns also has a 5" model called the Mini-cAntenna that's designed for a wider coverage area, but at a shorter distance.
Above we have the pigtail connected to our Buffalo 802.11g wifi card on our Compaq laptop. There aren't too many manufacturers that make wifi cards with external antenna plugs, but Etherdesigns has you covered there too. They sell wifi cards with a sturdy external connection.
In this picture we have the cAntenna on a tripod, and i must say it looks damn impressive.