balletballet says:

Black dance socks to complete your favourite ensemble.  Point those toes! Pink and white also available.

Manufacturer says:

Simply ballet socks which are perfect choice for dance students
Great price and excellent quality!
The sizes in order of smallest to largest are:
1. Child 6 - 8.5 
2. Child 9 -12 
3. Child 12.5 - 3.5 
Fabric: 100% Nylon
Colour: Black, pink and white