Hi Jalehia,
On your comb you may see a line, showing you where the comb was put together. Also look on the inside of the teeth of the comb, you will also see lines. A seamless comb is where these lines are not shown at all, that way you are not snagging or pulling your hair out. It's a smooth comb all the way around with no seams. If this sounds confusing let me know because I too didn't know what they were when I first heard of them.