Durable Design: Hourglass glass thickness from 1.55mm to 1.83mm. In addition, the hourglass timer uses shatterproof borosilicate glass and protective cover, which is not easy to break and is more durable than other brands of hourglass timers Booklet: Great ideas to help your child do things more efficiently and develop a strong sense of time. Each digital hourglass timer comes in a different bright color that looks impressive and is easy to identify WIDELY USE: Sand timer includes 1 minute timer, 3 minute timer, 5 minute timer, 10 minute timer, 15 minute timer, 30 minute timer in one kit. Large hourglass glass with sand for children students teachers. It can also be used as home office decoration and a practical timing tool in daily life. Made of high-quality plastic and safety glass, lead-free and chrome-free. It is safe for you and your children to use Packing quantity: 6 pieces.