To activate your LED Halloween Skull Necklace, remove pull tab and press button on pendant for 3 light modes - fast flash, blink, and steady light. Breakaway lanyard makes this necklace super safe for all. LED Colors: 3 Blue Necklace Length: 28" Pendant Dimensions (W x H): 1.75" x 2.25" Comes ready to use with 2 CR1220 Batteries.