The belt was an experimental project being developed by Marcus' father and Olivus Mynd at Overlord Industries. It works by scanning the wearer's torso and searching through over 200,000 pre-installed logos, and once identifying the logo, it will use nanites to give the wearer superhuman abilities based on the logo. It was originally set to be worn with a series of "AlphaShirts", which are leathery, track-jacket-esque shirts with different, simple logos, such as a flame or snowflake.
It was presumably designed for the military, but once they found out it would be too expensive to mass produce, kept only one copy of the invention. This copy was locked up at Marcus' father's secret room, along with the basic AlphaShirts.
Toward the end of thre game, it is revealed that it has been turned rogue by Overlord, and will corrupt Marcus' mind if he wears it any longer. He takes off the belt and drops it into the water below, presumably destroying it.
The belt is metallic and appears to be brass colored. It is covered in a square pattern and has a red circle in the middle made of glass.