From the seller:
A soft cotton yarn wrapped around by a shiny mesh yarn. It made small pompom on some of the mesh windows.

“Fiber Content : 80% Cotton, 20% Nylon
Needle Size : 4 mm. US 6 UK 8
Brand : ICE
Weight Type : 2 Fine: Sport, Baby
Length : 125 meters / 136 yds.
Weight : 50 gr. / 1.76 oz.”