Label states weight #3.

This 90% acrylic, 10% wool blend Lion Brand Neck’s Best Thing Yarn comes in six self-striping ombre color ways. In colors for all the people in your life, this yarn will make a great addition to your knitting kit. Use it to make accessories such as cowls, scarves, hats, mittens and more.
Brand: Lion Brand
Collection: Neck’s Best Thing
Ombres Content: 90% Acyrlic & 10% Wool
Weight Category: 3
Ombres Weight: 5.3 oz, 525 yds
Knit Gauge: 26 stitches on size 4 needles
Crochet Gauge: 20 stitches on size F5 hooks
Recommended Crochet Hook Size: F5
Care: Machine wash & Lay flat to dry