Do those seamless hair extensions work for relaxed african-american hair?

Yes it will work for African American hair, and it will match their hair texture. If you go online to Yahoo, or on Yahoo Answers, and type in Hair Extesnsions or Hair Weave, you will come up with lots of informations and videos that will show you styles and the actual videos. I've seen so many different styles on this videos that are very interesting and informative. You just need to find out which one is right for you.