Three things decide the selection. The mounting type — wall, ceiling, end mount or recessed — has to fit the location the inspector expects. The sign face has to be the color and lettering the local code allows, with red and green both common and self-luminous or photoluminescent versions required in some jurisdictions. The emergency unit has to deliver the required illumination for the required duration, usually 90 minutes, from a battery that is monitored and self-testing.
We stock edge-lit and panel exit signs, combination exit-emergency units, remote heads, emergency battery backups and replacement batteries, plus exit and emergency light parts for maintaining existing installations. Where a unit is self-diagnostic the specification table says so.