I have a question about hair extensions.....?

I was looking on the Sally beauty supply store website and I found 3 items in synthetic extensions, they were the Quick Clip 2 Straight Hairpiece which if u loom at the picture she's wearing a ponytail and the Taki Sybthetic Hair Pobytail....... My question is are these like u put your hair in a ponytail and add these around it and it makes your ponytail longer or are they saying u can wear then with a ponytail???? I really just want one that o cab wear to make my ponytail longer so if that's what they are great..... So if anyone knows what they are if they they do what I want them to do and yaaaa thanks for ur help