Hardened uplink/remote sensor package
From Halopedia, the Halo wiki
The HU/RS is a sensor package attachment for several UNSC helmets. It consists of a single attachment on the left or right side of the helmet, and can be employed alongside a External Command Network Module or CBRN module. By 2558, it was employed by Spartan-IV personnel employing the Military Police helmet.
The Scout and its GEN2 sucessor, Vigilant helmets also accept a different variant of the HU/RS, more visually similar to a pair of head-mounted bionoculars. This variant was employed by Jun-A266.
The HU/RS is compatible with the following helmets;
List of appearances