I'm on my boat in Beaufort NC for a fun weekend. Just hopped in ER to look at my older NL 643 5kW. Belt is a Dayco Top-Cog 15280 11A0710. Adjuster is right in center of range, so it fits well. Pretty sure I got the numbers right, but a bit blurry, so could be errors. Belt has about 2400hrs on it.