LED Badminton Set Shuttlecock Dark Night Glow Birdies Lighting for Outdoor/Indoor Sports Activities (Colorful) LED lights installed in the back of the cork, with On/Off push button. The lights turn on by a switch on the inside, so you can't easily shut it off accidentally Material: goose feather, feather, SMD lamps, electronic products This light-up birdies are very bright and durable, change colors and the batteries last 20 hours. Cork ball head and each shuttlecock only weights about 6.7g/0.24oz 4 x LED Feather Shuttlecock