For securely sealing seams on rainwear, bags, etc.

Flannel is a woven cotton fabric. Flannel is comparatively lightweight, but its roughened surface makes it very warm, absorbent, and wrinkle-resistant, as well as having a very soft feel. It's ideal for baby items like snuggle blankets, cuddle cloths, play mats, and much more. It's also great for sewing pants, pajamas, or bed linen.