Our flexible plastic Blue LED 27" Necklaces look great day or night! Each 27" LED necklace features blue LED fiber optics throughout. Click the on/off button to choose from 4 exciting flashing light functions. Our blue LED necklaces each open, close, and attach to each other for a length of light rope. Use our fiber optic necklaces to decorate for parties, parades, floats, bars, and more. Combine color for school spirit activities and Halloween costumes, too! 3 AG13 batteries are included, installed, and replaceable.