Dentist's Top Recommendation: This two-minute toothbrush timer is designed according to scientific principles, preventing children from feeling that brushing takes too long and losing interest. Cleaning Assistant: Fun colors, cute tooth shapes, and cartoon smileys make children love brushing their teeth. Safe Material: Made of durable PVC, high borosilicate glass, and non-toxic sand, making it very safe for children. After testing, the base at both ends is not easy to pull out or break, making it an ideal timer for children to brush their teeth. MULTIPLE USES - Very suitable for children to brush their teeth, and can also be used for learning or playing to help children do things more efficiently and improve their sense of time. An excellent gift for children and friends. Hourglass Instructions: You will receive 2 x 3-minute hourglasses. Please shake the hourglass to release all the sand and turn it over on the table to start the timer. For non-precision meters, please allow a deviation of 10%.