The mechanical countdown timer is very suitable for classroom, home and office environments. It can be used as an excellent classroom timer, countdown timer, study timer, silent timer, kitchen timer, timing clock, can be used for cooking, meetings, teaching, playing games, doing homework, etc.SpecificationColor:Black Material: Metal, PlasticSize: 6.9 x 6.9 cm / 2.72 x 2.72 inch (L*W)Display Length: 6.4 x 6.4 cm / 2.52 x 2.52 inchPacking List: 2 Pack x 60-Minute Visual Countdown TimerAdvantageMechanical Core Design - The mechanical countdown timer is made of ABS material and has a mechanical core design, so no batteries are required.60-minute Accurate Timing - The scale is clear and the timing is accurate. It can be set in increments of one minute, and the timing can be fast, up to 60 minutes. The mechanical countdown timer can help you arrange your time reasonably, concentrate and reduce distractions.Instruction1.Manual rotation timing, activate the timer before use, turn the button clockwise to the 55 scale position.2. Turn it counterclockwise to the time you need to time, and the bell will ring when the time is up.NOTE: Please be careful not to press hard when using it to avoid damage or malfunction of the counter.