I was wondering if you had to label each specific part as UL or if you could just put it in the letterhead for all parts you produce not just the UL ones??

I was wondering if you had to label each specific part as UL or if you could just put it in the letterhead for all parts you produce not just the UL ones??UL has some strict requirements for the use of their marks. What you're suggesting, in my opinion, is deceptive.

Al Rosen is correct, if you are registered with UL as the manufacture or sub-manufacture for some body else you will have the requirements for marking on hand. In addition, if you are still confused you can always call and ask your representative.
I did find a partial text for the standard.
“1.2 This program is intended to provide quick verification of material identification by means of an identification marking on the part, or on the carton in which the part is shipped, or in a specification sheet placed within the shipping carton with the part. This program is intended to eliminate the uncertainty of the polymeric material identity in the end-use product and to reduce the possibility of field problems caused by the use of incorrect compounds.”

Hope that helps.
:2cents: