That "H" Mall Store Rib Knit Scarf
You will need to double strand a worsted weight yarn. You can also use a (US) 13 (9.00mm) needle if you prefer.
For the double stranded, two color version, it took 4 skeins of Plymouth Encore worsted yarn. Two skeins of each with pleanty of yarn left over. I choose NOT to use fringe, but there would be enough if you wanted to add it. (US) 11 (8.0mm) needles. ~15 hours of knitting time.