Or not. Purely a cosmetic change.
I hate to say it because I like the design, but a waste of any Notum chip that could be used for CAS Symbiotic armor instead. Proof once more if any was needed that coders and producers spend their whole careers screwing up what the graphic artists and writers provide.
Very stingy of the devs to make an style preference 1) Cost a good deal of money for a base item hidden away in Fixer Shop and 2) Cost a vital resource and 3) Require tradeskills. This could have cost 1), to make it rarer, and something like Nano Circuitry Wirehttp://auno.org/ao/db.php?id=150918 for 2), and a zero-skill process for 3), and it would have been perfectly balanced.
Proof that they went too far is in the fact that players so rarely wear this.
Any Notum Chip too low to be used for CAS could be used on a Repairman's Hat
http://arcanum.aodevs.com/gadgets_repairhat.html or even a Physician's Cap
http://arcanum.aodevs.com/armor_physicianscap.html (I say 'even', because the Stalker Helmet
http://wiki.aodevs.com/wiki/Stalker_Helmet is superior in many ways) rather than this.