Covenant work light

Covenant work lights are small silver colored lights that are found on the ground during many Halo levels, most notably 343 Guilty Spark and Truth and Reconciliation.

Trivia
At first glance, it would seem that these lights are of Forerunner origin due to their placement and appearance. However, this is disproved by the fact that in Halo: The Flood William C. Dietz stated that they were the Covenant work lights. They are placed at areas of high priority or low light conditions, such as a swamp or a desert at night. They are rectangular in shape, project white light, often placed along walls, and point upward.Notice that most of the time during gameplay there is no one "working" around these lights.