High quality velcro sold by the metre in black and white. Velcro is available as either sew-on, or easy stick-on with adhesive backing (no sewing required!).
Stick-on velcro is 20 mm (3/4 inch) wide. Sew-on velcro is available in either 20 mm (3/4 inch) wide, or 50 mm (2 inch) wide.
Velcro sold as set, with both hook and loop sides.