It traps the light and glows blue in the dark. Since the necklace stays in the dark for a long time during shipping, if you hold it to intense light (fluorescent light, cell phone, etc.) when you first buy it, it gives a blue light when you enter the dark environment. Rope length: 55 cm Special for daily use and gifting to your loved ones. A product. These necklaces, which are the new style of recent years, will push you to collect. You can care for your product with a cotton, soft and dry cloth.