From then, the 8-string guitar has gradually gained more popularity in the progressive metal sphere, with bands like ...

Fanned frets “This is the model called 080S; it’s the fanned fret model. This is the first guitar I’ve had especially made for me. First of all the appearance is of course the first thing you notice ...

Simply put, the 8-string is a 6-string with two extra low strings. The most common tuning from low to high is F# B E A D G B E (that is, standard guitar tuning with low B and F# strings).