Lumistick Brand 6" standard glowsticks are 10mm thick and are rounded at both ends. They come with 25 removable connectors with necklace strings, you can hang them anywhere! you can use them as pendant necklaces or tie them to things. Once they start glowing, LumiStick brand glow light sticks will last you all night. They will glow super bright for 8 - 12 hours. Then, they will start to fade out but may continue to emit some light for up to 36 hours. These LumiStick brand glow light sticks are fresh from the factory. They come directly from the factory and were manufactured just a few weeks ago. We are constantly getting new shipments from the factory, so you know these are as fresh and new as they come. They have a shelf life of 2 years. Inside the glow light sticks are two chemicals that emit light or glow when they are mixed together. Inside the glow light sticks is a thin glass tube, when you bend it for the first time, you break the inner glass tube. This mixes the two chemicals together. Just shake it up and presto -- it starts glowing like magic! Lumistick brand glow light stick glow-in-the-dark products are non-toxic. They are not radioactive and they are not flammable. They almost never break open, but if they do, the chemicals inside can be washed off skin and clothes with ordinary soap or detergent.