Review (5/5): Takes some getting used to
It does take some practice to figure it out, but works great once you do. I just wouldn't recommend it for everyone. I have thick hair that goes a couple inches below my shoulders, and I don't think they'd work for anyone with thin or shoulder-length hair. You can also only roll it in an upward direction. If you try rolling it downwards, it won't catch the whole length of your hair and will roll out. It also helps to leave a tail and tuck it up under the bun maker after you've got it in.
With that said though, the slap bracelet-like bun makers come wrapped in pretty realistic looking fake hair in a good array of natural hair colors. They do stay in all day once you get the hang of it, though I still put an extra hair tie around it for piece of mind and to hold down any loose strands. They're my go-to for putting a bun in for work.