The site says they are safe. Are there any raised edges or seams?
Do they have springs that could grab hair?
Have you tested these on people with hair longer than mid back or waist?
Are there plans for any instruction booklets or perhaps how tos online?
Are there plans to make other types of hair accessories such as plastic hair sticks, slide combs, headbands?
There is a market out there for seam free hair accessories that can hold really long hair. If you can come up with those products you'll get some customers that other companies aren't.
Could you tell us a bit more about you? Do you wear the clips? How long is your hair? Do you get headaches from wearing them?
