Velcro. Coloured Scanning Electron Micrograph (SEM) of nylon hooks and loops in Velcro material. Velcro is used as a common fastener on clothes and shoes. It is a nylon material manufactured in two separate parts; one with a hooked surface (blue, at lower image) and the other with a smooth surface made up of a series of loops (green, at upper image). The loops are loosely woven strands in an otherwise tight weave. The hooks are loops woven into the fabric and then cut. When the two surfaces are brought together they form a strong bond, which can be peeled apart. Magnification: x15 at 6x6cm size.