Most jailbreak-tweaks are designed to better take advantage of your iPhone, but at Double Dock is the question what the point of it is. With Double Dock, you can instead of four solid apps in your dock extend this number to ten apps. These icons are in two rows on your screen placed where a normal row of icons on your home screen is lost. You also need at least five apps in the first row have to stand in the second row to use.
Because the positions of the appiconen not quite properly aligned is Double Dock aesthetically disappointing. It is the question which ten applications you at all times within reach should have. Especially because you have to pay 99 cents for Double-Dock is the jailbreak tweak a bit disappointing. A better alternative is InfiniDock , where you get a ten icons which you can scroll back through your dock.
Double Dock for 99 cents to download from the repository of BigBoss.