78% Tricel® triacetate (rayon), 22% nylon.

From the early 1970s, and used in both crochet and knitting patterns.

Note: This is not the same as Patons NA Promise, which was sold in the 1980s.

“In the United States triacetate was introduced under the trademarked name Arnel” - Encylopaedia Britannica.