INST Solar Fiber Optic Butterfly String Lights Features 12 solar-powered fiber optic butterflies Solar powered panel with a built-in rechargeable battery, which could be replaced with a NEW Ni-MH battery if it necessary! 2 different modes of glimmering : flash and steady on Total length: Approximately 11 Ft. The length from the solar cell to the first butterfly is 6 FT. Wide applications, great for various celebration occasions, especially for outdoor activities in the garden or lawn