The box comes with two pins, and you can get them in several different colours- depending on hair colour (I, of course, got the ones for blonde hair) I managed to throw away the packaging but it was actually quite useful- there were several pictures of hairstyles and tips for use.
As you can see they aren't much longer than a regular pin, but the metal is thicker and more sturdy. Again I was a bit sceptical that they'd hold the weight of my hair (as it's pretty darn long at the moment) but it definitely does, once you've twisted it into the bun :)
Basically, I am thrilled with them- they work far far better than I ever believed they could, and I highly recommend them to anyone who likes wearing their hair up. (My sisters hair is a lot shorter than mine (about shoulder length, but it is thicker) and they still work well for her, though any shorter and I think the pins would be too big for the amount of hair you have. )
Have you tried Spin Pins?