From the publisher's website:
MECHNOIR is an alternative Player's Guide for Technoir: High-Tech, Hard-Boiled Roleplaying. It includes nine new shiny training programs, six big stompy mechs (or 'rigs'), and the two transports that bring them to the battleground. There's special rules for destroying the tags on your enemies' rigs and transports and a section for how to deal with scale when hardboiled criminals go up against hard-cased machines.
Bundled with the player's guide are three new Transmissions that outline the major colonial factions on Mars: The Chosen, the Shiat al-Raj'a, and the Martian Autonomist Union.