The RX-81ST G-Line Standard Armor is an RX-81 G-Line series variation. It debuted in Kunio Okawara's Missing Mobile Suit Variation (M-MSV).  It was revamped and updated for the video game Mobile Suit Gundam: Battlefield Record U.C. 0081.
The kit includes newly molded parts and may be converted into a regular G-Line unit by removing its armors. For increased firepower, an optional pair of gatling gun smashers can be mounted on its back.
RX-81 G-Line
 
Because the mass-produced GM series prioritized efficiency, its specifications are significantly lower than those of the RX-78-2 Gundam. The RX-81's design keeps the Gundam's specifications while expanding the mobile suit's arsenal of weaponry and armor by integrating the FSWS, giving it several forms. Backpacks may be swapped as needed, with two thrusters on the ground and six in space.
 
RX-81ST G-Line Standard Armor
 
The RX-81ST G-Line Standard Armor is the standard configuration of the RX-81 G-Line and may be used at all ranges of battle, making it an incredibly flexible suit. It can be outfitted with additional armaments on its bag for increased assault strength when necessary. When fully equipped, it mounts a backpack with two additional medium stabilizers to enhance operation time.
Parts feature
 
HEAD
The head is molded so detailed that it shows the internal twin eyes inside the clear blue visor.
WRIST
It is feasible to shift the direction of the forearm around the elbow by incorporating a roll axis in the elbow joint.
LEGS/ FEET
The range of motion is increased by bending the knee downward.
　　
BACKPACK
There are two sorts of backpacks included: one for use on the ground and one for use in space.