The Gundam F91 (F91 standing for Formula 91) is the titular mobile suit of Mobile Suit Gundam series.
Mobile Suit Gundam F91 1/60 Big Scale Model Kit
Another F91, colored dark blue and yellow, is piloted by Harrison Martin.
Reduced in height compared to its famous predecessor (15.2 meters compared to 18.5) and mass (19.9 tons fully loaded while the RX-78 took off fully loaded at 60.0), the F91 was immensely more powerful.
It is armed with a pair of machine cannons in the chest, Vulcan guns in the head, a pair of back mounted variable speed beam rifles, beam sabers, newly developed beam shield.
That was much more effective than the solid state shields used by past mobile suits, and can be optionally equipped with a beam rifle and a beam launcher.