This is a Tuny Glow Ring, which is a party accessory designed to glow in the dark after being snapped and activated. 

Product Type: Glow-in-the-dark ring made from a small glow stick.

Features: Designed to last for hours and is intended to be fun and easy to use.

Safety Warning: Contains small parts and is not suitable for children under 3 years old due to choking hazards.