To activate your New Years Necklace, remove the pull tab & press the button on back. Choose from 5 light functions: Multicolor flashing, slow color change, red blink, blue blink & green blink. LEDs: Red, Blue, Green Dimensions (WxH): Pendant – 3.25″ x 1.75″ Necklace Length – 36″ New Year LED Charm Necklaces come ready to use with 3 replaceable AG13 Batteries