how many digits series number has?

  1. I saw 8 digits most of the time, but sometimes they are 7 digits. Why are there diff # of digits?

    Btw, I heard fakes have same series #. Which ones shall we watch out?
     
  2. Holograms beginning with 0-9 will have 7 digits. Holograms starting with 10 or 11 will have 8 digits.
     
  3. The most common are the ones ending with:

    5454
    8184

    Those are mass produced fakes as seen on eBay.