Hair type: fine and straight

These are great!  I use them for martial arts (you can't use any hair restraint that contains metal... so these are a godsend).  If you have fine hair, I'd recommend the "jumbo" type.  I use the jumbo medium and it's thick enough to add fullness to my bun (that's the jumbo part) and the medium size (smaller diameter when clipped into a bun) is perfect.  I would need to grow my hair to my waist (it's very fine) to have enough hair to put in the jumbo large.

I have the non-jumbo type as well.  It's too flimsy if you have fine hair.  It doesn't lock firmly in a circle.  The mini ones are great for putting at your temples overnight... then you have little ringlet accents in the morning.

You do have to experiment a bit to figure out where you need to start rolling in order to have a snug bun... but once you figure it out, it's a breeze.  I like to put an additional elastic hair tie around the bun to help keep any loose ends from coming out.  Again, if my hair were longer, that wouldn't be an issue.

I wish I had these when I did ballet when I was younger!