Ninja Lites use 2 LED lights with a CR2025 battery to brighten the sky, and snow, on the darkest of nights. They weigh in at 1.7 grams. Simply slide both lights over oposite ends of the battery and attach them to either side of your favorite disc with a strong transparent bonding tape. Using a clear weather proof tape like Gorilla Clear Repair, Scotch Transparent Duct Tape or Duck Brand All Weather Repair Tape will allow you to NINJA LITE up and throw in all weather conditions without worry of the tape falling off. So, NINJA LITE up and throw well!!!