non metalic knives in NYC and other questions

[Doni Patrisso]

Hello I was wondering if its illegal to carry the non matalic plastic/glass knives that are sold like the "CIA letter openers" such as:
http://www.shomer-tec.com/80.html (The first one, I specificaly am asking about this one)

and

http://www.agrussell.com/agrussell/agcialo.html

If they are legal, would these still be considered illegal due to them being double edged?
Do they even count has having an edge?
Doesnt a knife have to be metal to be considered a knife??
Thank you for any help.
Much confused,
-Doni Patrisso


[This message has been edited by Doni Patrisso (edited 05-27-2001).]