Actually, there is no unified stander in the hair industry. Different suppliers have different grade names.

For example, the same hair called 5A in one company might be called 10A in another.

However below with our grades guidance for your reference:

7A Human Hair:

Hot sale on Aliexpress

100% human hair, Non-Remy, quick-change human hair, do not recommend to dye. Last 3 months with proper care. 

8A Non-Nemy Hair:

Hot sale on Amazon

Acid bath, cuticles removed, soft & silky, tangle-free, can be bleached to #30 the lightest. Last 6-12 months with proper care. 

9A Virgin Remy Hair:

Bestseller for wholesaler & distributor

Cuticle-aligned Remy hair, bouncy and silky, can be bleached to #27 the lightest. Last 2 years with proper care.

10A Raw Virgin Hair:

Suitable for elite customers

Unprocessed virgin hair, silky & gloss, can be bleached to #27 easily. Last over 3 years with proper care.

12A Single Donor Virgin Hair:

Suitable for Salon restyle & recolor

Each bundle from a single donor, all cut from young girls, can bleach #613, can be dyed and restyled repeatedly. Last over 5 years with proper care.