Great for sewers, skaters, costumers, theatrical productions, pageants, ice capades and bridal wear. Wear at raves, clubs and use for glow in the dark craft and art projects. Expose phosphorescent sequins to bright light and then they will GLOW in the DARK. Large discs for bold projects. Three quarters of an inch in diameter with center hole. Size and pack specifications: 20mm is approximately 3/4 of an inch. 100 sequins per pack.