This is Bandai149834 MS-06S ZAKU II
The MS-06S Zaku II Commander Type is a Mobile Suit introduced in the Mobile Suit Gundam television series. This variant looks very similar to the standard MS-06F Zaku II, so much so, that the Earth Federationcan generally only tell the difference from color schemes most pilots apply to their units and the increased performance of this version.
Technology & Combat Characteristics
The S-Type Zaku II features a squad-leader "antenna" that is mounted on the head on the Zaku II for enhanced communication capabilities, which is used to designate squad-leaders or higher ranking pilots from other squad-members or lower ranking pilots. It also featured a more powerful powerplant, which in turn, gave the S-Type Zaku II greater thrust and acceleration. However, since no changes were made to the fuel tanks, the S-Type's operating time is shortened as a result. This allowed them to move at speeds 3x faster than a standard Zaku II. This made it incredibly dangerous in the hands of the ace pilots it was handed out to, such as the "Red Comet" Char Aznable, who sank 5 Magellan-Class Battleships in the Battle of Loum.
It was noted in an extra feature that came with the Mobile Suit Gundam: The 08th MS Team DVDs that the 3 times faster figure came about from Char's clever use of terrain and debris to boost off of, saving fuel and increasing his speed compared to normal.