Review (5/5): Works very well, sturdy and a good value!
I'm always looking for simple but pretty ways to pull my hair up so I decided to try this. It's basically a gigantic bobby pin on steroids, 4 thick metal prongs that are curved to follow the shape of your head. I found the written instructions confusing but searched on YouTube and found some videos that explain it well. Once I got the hang of it I was able to do the messy bun style in about a minute.
My hair is fine and slippery, and I have a lot of layers, so there is some hair poking out when I do it, but it's much better than what I would be able to achieve with bobby pins. I expect it will work better once my hair grows out a bit. You can make these hairstyles as tight or as loose as you want depending on how much hair you gather in the pin as you flip it, so it's good for those that have a lot of hair to wrangle as well as those who get headaches if their hair is pulled back tightly. If you have past your shoulders that is wavy or curly (like the model in the diagrams) I think that is ideal, but I think you can make it work with most hair types.
For less than $5 for a 2-pack it's worth a try, and if it doesn't work for you, pass it on to a friend with a different hair length/texture.