Glows in the Dark after absorbing the light. Very Cool! EmbTao is the first brand of developing Embroidered Glow In Dark Patch..Measures 3.5 inches wide by 3.5 inches tall..Hook backing patch for attachment to tactical hats and gear. The loop tape comes for free..Washable and Durability. Safe & non-toxic..Package: 1 pcs hook backing patch. 1 same sized loop tape packed free.