The GAIA (Giant Attachment Interface, Armed) Piece system was a project considered by the UNSC to weaponize volunteering macros into mobile weapon platforms. Essentially batteries, weapons and tactical equipment attached with straps, via sensing inputs from the muscles of the macro would both direct and fire weapons with simple hand gestures. The project is ongoing, however- many issues have arised regarding multiple sections of GAIA. The weight, reliability, supplying and safety are among some of its biggest concerns.

The only effective prototype GAIA piece seems to be the I-Block, which is a singular C-RAM unit attached to a thick, ballistic armored band patterned with ERA.
The C-RAM units have shown to be great at both intercepting projectiles and light vehicles - as to be expected.
...Also I just wanted to see a kangaroo suited up lol