Revlingar, an old form of knitted wrist-warmers worn by fishermen of old on the Swedish West-coast. They have a special shape and are very functional. I have never seen an old pair of revlingar. I have read about them and seen pictures and descriptions of recently knitted ones. They all have this shape.
These are knitted in garter stitch. I guess you could use any other stitch pattern that you prefer. They are excellent projects for learning how to knit, and also nice gifts.
I used a thin 2-ply yarn from Filtmakeriet and needles 2,50 mm. They are 12 cm wide (I casted on 32 stitches) and 38 cm long, not including the decrease part that is 5 cm. When I had three stitches left after decreasing, I knitted a 55 cm long i-cord. You could make a braid or make a crochet chain instead if that is what you prefer. Just make it long enough to wrap around your wrist a couple of times. One pair of this size used about 85 grams of yarn.