Size: The size of the pendant is shown in Figure 2,Adjustable chain length. Style:The luminous stone stores the light energy under the irradiation of natural light, sunlight, ultraviolet light, etc., and after slowly stopping the light emission, it is slowly released in a fluorescent manner, so the light can still be seen at night or in the dark.After the luminous stone stops emitting light, you can illuminate it with a mobile phone light or the sun, store the light energy, and it will shine back into the darkness again. Tips: Don't wear it when bathing,Avoid contact with hairspray, perfume, skin care products together. We promise: reply to your message within 24 hours, dissatisfied with 100% refund. About jewelry: the price is moderate, nickel-free and lead-free, non-allergenic, just place an order if you like it.