These are the glow-in-the-dark solar gear markers that we provide to members of our Sniper Night Vision Operator Course.   We use them to mark zipper pulls on tactical packs, drag bags, etc.  2″ overall with a keyring and additional gear clips. Glows for up to 10 hours. Battery free. Recharges by sun or other light source.   Available in Blue, Green, Orange,  or Yellow.