Kamaka has been making ukes for over 100 years now and the 8 string tenor was first created by them. Also known as "the Liliu VIII," the Tenor 8-String was designed by Sam Kamaka Jr. in 1976 to commemorate the Bicentennial of the United States.
Pictures show the exact ukulele available here. Corey gives us a raw sound sample of this same model.
The 8-string has all four strings doubled, with the third and fourth pair tuned in octaves. Played with standard ukulele tuning and fingering, the sound is rich and unique. The paired strings are played together like a 12-string guitar. It creates very smooth strumming and is a big part of the Hawaiian sound.
This one we just received is exceptional, as you can see.