The EIB3016 has way more features, interchangeable hard-wired interconnect (different optional plug-in wireless interconnect module), 3rd LED for fault alerts, same base as EIB166E and all Brooks mains powered Alarms.
EIB3016 - Mains powered Photoelectric Smoke Alarm with built-in rechargeable, non-removable, non-replaceable, life-of-Alarm 10-yr lithium back-up