One (1) 3 in 1 Stacking Grid Light modifier * It is designed for CANON 580EX/ 580EX II * The JJC Light Modifier was designed to produce 3 different size of light spread (Small, Medium and Large) * when aligned and stacked two grids together, produce the smallest spots of light. * Stack the small grid into the bezel to produce large size spots of light, for medium size spots of light just stack the larger size grid into the bezel.