This machine is an absolutely great tool for making stockinette tubes quickly and easily! I had mixed feelings about whether or not to purchase this thing based on negative reviews I had been reading. I have to say that I am extremely impressed, and it has been worth every dollar spent. They even throw in extra needles in case any break, although I can't even think how you would break one, they're that sturdy.The circumference of a finished beanie in Caron - Simply Soft (doubled for warmth) is big enough to fit a child to medium-sized adult head with a little wiggle room. My boyfriend has a large noggin and he can squeeze into one of the hats, but it isn't very comfortable. A finished tube, laid flat and unstretched, is close to six to eight inches wide, depending on the yarn used.The most important advice I can give you is to choose the RIGHT YARN for the machine. I have used a wide variety of weights and fibers and here is what I think are the best choices:1. Worsted Weight - Caron Simply Soft. I can't say enough about how great the Addi Express works with this yarn. I've made scarves, hats, and blanket panels and they turn out great. Not a dropped or twisted stitch to be seen with more than 800 rows on the longest piece I've knit. I cast on and just crank the handle, most of the time I just watch TV and mindlessly knit, that's how dependable the combination is!2. Worsted Weight - Lion Bran Vanna's Choice. Very occasionally the machine doesn't quite catch a full stitch and splits the yarn on a needle, but it has never been a huge problem as long as I keep an eye out and have a crochet hook handy.3. Worsted Weight - SMOOTH wool yarns. If your yarn is boucle, plied loosely, or splits easily, you will not get a good fabric out of this machine. Wool blends have worked amazing for me, but I have yet to try any of my higher-end wools on it for fear of ruining them. I would stick to acrylics until you're comfortable with how the machine works.Bulky yarn will not work well at all, you'll end up with a stiff chunky fabric that is a pain to keep on the needles. I haven't experimented with smaller weight yarns either, but your fabric will obviously turn out lacier than worsted.I have no idea why, but Red Heart Super Saver absolutely kills this machine. I've tried many combinations, and I am constantly dropping stitches when using this brand, and the machine makes a terrible clicking noise. It's baby melter yarn, so I can't say I'm disappointed, I just would have loved to mindlessly crank out tubes of the stuff for charity scarves since I have a lot of it sitting around.All-in-all, I'm pleased with this purchase, and I would recommend it to anyone looking for a solid starter machine with a relatively low cost compared to professional machines of the same size.