Before Pete Made just the 7 Plus or 10 Plus,
He made cords 7, 8, 10 & 12. These are all the American Series.
Eventually, I think he settled on 10+ and 7+ models as his primes for his website, but he also did Plus versions of several other thicknesses.
These cords are a pair one of his 8+
They would slot in between:
7 Plus - thickest 7 gauge
8 Plus - the two cables for sale here in this ad
10 Plus - thinner 10 gauge
They would be suitable for any equipment, especially good for those with higher power draw, I used them on subwoofers and amps.
I have Some 7+ cables, and these 8+ look and sound the same to me.
They sound better than my 10+ on amps, more powerful, as you might expect with a heavier gauge cable.
These could be used with powered speakers, a pair of amps, or you could run one from the wall to an UberBuss, and the other to your piece of gear - I used them like that too for a while. I considered them more of an analogue/direct substitution for my 7+ cords than for the 10+ (which I use on gear with lower power draw).