NGSF91 01 RGM-111 Hardygun

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 model kits are generally exempted from 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.