E2-BAG/1/7
From Halopedia, the Halo wiki
E2-BAG/1/7 is a United Nations Space Command infantry unit
It is of unknown type or size, although it's presumed to be a Marine unit.
E2-BAG/1/7 was interviewed by Dr. Robert McLees on multiple UNSC and Covenant vehicles and firearms that will appear in Halo 3. Some of these interviews were posted on Bungie.net's front page.
