I didn't even know that these were around until there was a mention in a forum here. I watched a YouTube clip and they seemed to good to be true.
I found mine on trademe. Not sure where you would normally buy them from. I have long fine hair. I had grown my fringe out and wanted a fringe.
Opened the small clip up, gathered my soon to be fringe to the middle of my forehead, put the small clip around the hair at the roots, then slid it down to the length I wanted. There is a level that makes sure you have a straight line.
Then use SHARP scissors, cut very fine snips at 45 degrees to the clip (below the clip not above). Once you get to the end, the clip just slides off. Walaa brand new fringe! It honestly took me longer to section the hair than cutting.
I have used this multiple times on my fringe and you can get different looks by holding at different angles.
The same goes with the large clip on hair. Not sure how it works on short hair. You would probably need a friend to help you. I wash my hair, when it's wet, I put the clip in. I get whoever is around to make sure the level is straight and they cut along to get that perfect straight line. It's So easy to get different looks, lift it away from the head for layers etc
I bought these full of excitement at the time as I am quite a fan of DIY hair cutting and anything that helps to get a good cut by yourself I am up for. Unfortunately these aren't the miracle clips that they are made out to be I ended up with a butchered fringe and very squared off layers with these I do much better with the old pony tail over the head trick than these to get good even layers. The leaflet that came with these makes it look so easy - that you slide down and cut, but I had to make repeated cuts and found it bevelled out in areas and looked really obvious that I had cut it myself. I haven't tried using these for asymetrical fringes or side fringes but these may work well for that purpose. I generally just need to trim my fringe and give my hair some layers to stop it from weighing down and I can get that easier from more traditional methods.