How do you spell a Byron pen in french?

There is no direct translation for "Byron pen" in French. However, you could describe it as:

* Un stylo Byron: This is the most straightforward option, simply using the brand name "Byron" followed by the word for pen, "stylo".

* Un stylo de la marque Byron: This emphasizes that the pen is from the Byron brand.

The specific wording would depend on the context of your sentence.