Cat7 Ethernet Cable?

[The DirtMerchant]

I'm looking for a 50ft or so Cat6 cable on Amazon and came across Cat7 cable...
What is Cat7? Flint mentioned in a thread when I searched that Cat8 would be able to power some electronics or something...what is difference between Cat5/6/7/8?

 

[Akula]

Cat 5e is good for gigabit levels
Cat 6 has a tighter twist to the pairs allowing for two way communications and higher speeds on shorter runs (10Gb)
Cat 7 has yet more shielding, and the pairs themselves are shielded. This shielding must be grounded. So you're getting longer runs at those higher speeds but it's rather more $$$ and stiffer.
Cat 8 is pretty new and allows much higher speeds yet.

For home use in the near future, Cat 5e is probably more than good enough. You can go Cat 6 if you want to be somewhat future proofed (I'd only bother with this if I were wiring the house backbone and I didn't have much ability to change it out later if need be). Cat 7 isn't worth it for home use. Cat 8 likely less so.