You don't need a battery. Mechanical time manager, no battery, slight pendulum when walking, crisp ringtones at of time It is easy to see. It provides a visual effect of the rest of the time. easy to use. Just turn the knob clockwise to get the time you need you can better remind the children that time is up. Better time management Three placement positions - 1. Two folding legs can be opened and placed on a flat such as a table and counter. Can also hang Display type: pointer Movement: quartz Power type: battery Shell material: ABS Product size: about 190 x 190 x 40MM Color: black Package Contents: 4 x 60 minute timer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.