Future Ratchet was Ratchet wearing the suit Ratchet acquired prior to the start of Quest for Booty, it was used for the entirety of the game. The suit was commonly referred to as "the Scavenger Suit" by the fandom, although it is unknown if this name came from an official source.
The symbol on the belt buckle is the icon for Apogee Industries, and the suit is most likely one of the industry's products.
Future Ratchet reappears in Ratchet & Clank: All 4 One as a skin exclusive for Ratchet. It is obtainable after collecting 5 Hero Bolts.
Behind the scenes
It seemed quite likely that Future Ratchet would be the starting armor in Ratchet & Clank Future: A Crack in Time. However, the game started with Ratchet wearing the Holoflux armor and the Scavenger suit never made an appearance. Although concept art suggests that the armor was originally planned to be in the game. There was even a model of the suit created.