Fine ribbed knit with good stretch and recovery, similar to a lightweight sweater rather than a T-shirt jersey — the rib keeps the turtleneck standing up rather than collapsing. Hand wash cold or machine wash on a gentle cycle inside a bag to protect the rib structure, and reshape the neckline while damp, easing it back to a close, upright fit rather than letting it dry however it lands. Lay flat to dry and avoid high heat, which relaxes rib knit's recovery more than a flat-knit fabric.