One side is woven with many loops (referred to as "suede"), and the other side is woven with many even small hooks (referred to as "hook surface"). After the two sides are aligned, a slight squeeze will hook up the ring, which can play the role of connection instead of buttons, snap fasteners, zippers and so on. It is characterized by convenient use, time saving, fast sewing speed and softness.
It was invented by Mestral, a Swiss engineering teacher. It is said that he likes outing and hunting. Whenever he comes back from the suburbs, he often finds some Bidens bipinnata seeds sticking to his clothes. It is very troublesome to remove these Bidens bipinnata seeds, which aroused his interest. So he took out a seed from his clothes and observed it carefully under a magnifying glass. He found small hooks on the bristles of the seeds, and it was these small hooks that caught the yarn on his clothes. From this, he thought that if these similar hooks can be made on the belt, wouldn't it be possible to make the belts overlap each other instead of buttons and zippers? Inspired by Bidens bipinnata seeds, after 8 years of careful research, he finally designed a stereotyped product, which is the origin of velcro belt.
I hope the above answers can help you.