Double sets of speaker binding posts on Krell ?

I bought a Krell FPB300 amp recently,unfortunately without manual.

What are double sets(TWO pairs) of speaker binding posts for? Bi-wire?

If so,I can use TWO PAIRS of speaker cables ,connected to EACH PAIR of binding posts,for driving LOW and MID-HIGH
respectively?
Or,I should buy ONE PAIR of bi-wired speaker cables,just connecting to ONE PAIR of binding posts on Krell?

Probably simple question for you experienced Krell users.
Thank you in advance!