DT Competition Straight Pull 2.0/1.8/2.0 mm

You have to use 2.0 mm nipples / straight-pull

Spoke Lenghts for DT Swiss System-Wheels can be found with this tool:

DT Swiss Productfinder

For Straight-Pull hubs you can use the DT Swiss Spokes Kalkulator.

Seriennummer DT Swiss Nabe