The self-gripping fastener consists in two elements :
The hook element has a surface made of hook, mushroom or arrowhead - shaped gripping part.
The loop element has a surface comprising of loops fibres.

These elements are made of  textile or plastic.

The closure is obtained by the combination of the two elements.
When the two elements are applied to each other (i.e the “closing”), the hooks are engaged into the loops.
The "opening" is obtained when the hooks release the loops.