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 "5" base (abbreviated BS5). The BS5 is the size of a Monitor (MT) sized ship.
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