Our flexible blue plastic neon necklaces look great day or night! Each LED necklace features blue LED fiber optics throughout. Click the on/off button to choose from 4 exciting flashing light functions. Our bold 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 . 3 AG13 batteries are included and installed and can be replaced.