Care to actually answer? I guess I'm right then since you didn't explain a thing... good job broski
Semi-Powered Infiltration Armor, colloquially called "SPI Armor", is a powered armor system used by the SPARTAN-IIIs. Though far more advanced and far more powerful than the ODST combat suit, it is less advanced and less powerful than the MJOLNIR armor used by the SPARTAN-IIs. Its main benefit was that it is drastically cheaper to produce than the MJOLNIR armor. This armor is designed with an emphasis on stealth rather than raw power. It features photo-reactive panels that mimic the surrounding textures which were developed by UNSC scientists. It has been described as "part legionnaire mail, part tactical body armor, and part chameleon." It lacks the energy shielding of the Mark V and VI MJOLNIR armor designs, and a single "splash" from an enemy plasma weapon melts the suit's photo-reactive panels, rendering its camouflage capabilities useless.