In Starfire, the "Base" is a ship-like unit that has station-keeping drives that enable it to hold position within a star system. These drives take very little space, so a base typically has more internal hull spaces available for weapons and defenses than an equivalent-sized ship. Since bases can hold position they are most often used to defend warp points and other fixed position locations within a star system.
This miniature is a representation of a size "4" base (abbreviated BS4). The BS4 is about the same size as a Super Dreadnought (SD), which is larger than a Battleship (in Starfire). At this size of unit, the lack of drives means that the BS4 will be able to mount around twice as many weapons as the Super Dreadnought ship hull.
Starfire miniatures are "squadron scale" (0.5"-5") miniatures designed for the Starfire Quick Start Rules for miniatures. You can downloads the rules from Wargame Vault at
http://www.wargamevault.com/product/214246/Quick-Start-Rules-for-Miniatures
Starfire products can be found at
http://www.wargamevault.com/browse/pub/9056/Starfire-Design-Studio and
http://www.starfiredesign.com/starfire