This yarn is a single ply. It’s intended to be held together with another yarn to reinforce the heel in knitted socks.

It comes in 4 natural colors. A dark grey, a medium gray a light grey and white. Shop on line at Ull.no.

From Ull.no website:
“Mainly used as an extra thread when knitting heels and toes. The yarn has not been washed after the spinning. Approx. 500 m/547 yd per 100 g, Nm 5/1, 100 g per skein.”