This pattern was designed to be a quick project so you can walk out the door in style tomorrow. Any worsted weight yarn will do, although I prefer synthetic fibers that have easy care instruction so the boot toppers can be tossed in the washer with a load of similar colored clothes and go through the dryer with ease. Using natural fibers or more delicate synthetic fibers (like Caron Simply Soft) will change the care, so follow the directions on the skein of yarn. This was also intended for a stouter yarn that will keep the fluffy shape of the stitch more than one that will drape. Think Red Heart Super Saver more so than Caron – although I love Caron and have a very exciting project for March coming in the last week of February.