The 1/100 Silhouette Formula 91 Model Series (NGSF91) is a line of Gunpla kits of the Mobile Suits from Mobile Suit Gundam Silhouette Formula 91 in UC 0123, a spinoff of Mobile Suit Gundam F91. As with higher-end Gunpla kits released in the early 1990s, most of the line's kits feature System Injection - also known as "Iropla" (イロプラ, "color plastic"), a process that molds multiple colors into one piece.
Modelers refer to these kits as "Old kits" (旧キット Kyū kitto?) when comparing them to the more recent Premium Bandai exclusive Reborn-One Hundred releases. Reissues of these kits can be distinguished from their original releases by their glossy box print (as opposed to the original's matte finish) and inclusion of plastic content information on the box's side flap. The reissues also omit the "ST" mark, as they no longer meet the requirements of the Japan Toy Association's Safety Toy (ST) Standard. In addition, reissues from 2019 onwards will bear the blue Bandai Spirits logo.
|NGSF91 #||Model||Release Date||Yen Price||Notes|
|1||RGM-111 Hardygun||1992 April||¥1,000||First kit in the series.|
|2||RXF-91 Gundam RXF91||1992 May||¥1,400||Features color molded markings on shoulder armor parts.|
|3||XM-07G Vigna Zirah||1992 July||¥1,000||Parts and color variant of NGF91-02. Includes Gundam-type head parts.|
|4||F71B G-Cannon Magna||1992 July||¥1,000||Color variant of NGF91-01 with new head, torso, shoulder armor, and cannon parts.|
|5||RX-99 Neo Gundam||1992 September||¥1,700||Unit 2 colors with green beam shield. Includes transformable Core Fighter and MS Handbook.|
|6||RXF-91A Gundam RXF91 Kai||1992 December||¥1,800||Re-release of NGSF91-02 with new parts.|
|7||F90III-Y Cluster Gundam||1993 March||¥1,200||Includes transformable Core Booster. Hardpoints are compatible with the Gundam F90's expansion packs.|
Yen price excluding 5% tax (8% from 2014 to 2019; 10% from 2019 October onwards).