Restrictions for Tourist L visa?

Hi - I’m an American with a 10 year Tourist L visa. Are there any restrictions for using this visa?

I am taking the following flight from Berlin to New Zealand: Berlin — Beijing — Shenzhen — Auckland.

Am I allowed to use my L visa to transit through China, even though I’m not coming from the US and it’s not a round trip ticket.

Or would I need to apply for a special transit visa?

Thank you,
GH