The SentinelEar MK-II is a full cochlear replacement system built around a military-spec acoustic intelligence processor capable of real-time gunshot triangulation to within 1.5 degrees of arc, individual footstep counting and gait analysis up to 60 meters, whisper amplification to conversational clarity at 40 meters, and encrypted squad communications via a hardened short-range radio node embedded in the mastoid. The acoustic AI runs continuously, flagging threat signatures and feeding data to a neural HUD overlay without requiring conscious user input. All communications are encrypted using Arcturus' rotating military cipher protocol.

The MK-II is standard-issue hardware for Arcturus-contracted military units, GRPD Tactical Response, and select GLMZ corporate security divisions with black-level clearance. Restricted distribution is enforced aggressively — Arcturus employs hardware kill-switches that can be remotely triggered if a unit is reported stolen or used outside sanctioned parameters. On the black market, deactivated or jailbroken units are among the most sought-after pieces of tactical hardware in the city.