Specifications Movement: Multifunctional Quartz Movement. Type:Fashion & Casual Features: 3 atm waterproof, Luminous Hands, Calendar, Hour, Minute, Second Water-resistant depth: 3ATM Watch weight: 157g Band length: about 245mm (available to wear) Bandwidth: about 22mm Case size: about 44.5mm Case thickness: about 14mm HOW TO USE THE BUTTONS? Start/Stop Button – Press the button, the chronograph will start to work; Press again, the chronograph will stop working. Crown - Pull out to the first grade to adjust the calendar. Crown - Pull out to the second grade to adjust the time. Reset Button – Press the button, the chronograph will back to the original position. Luminous Function: Luminous parts glow in the dark continually after absorbing enough light. Function Demonstration: DAY Indicator 24 HOURS (the middle one): 1 circle = 1 DAY DATE dial (the bottom one): 1 circle = 1 MONTH Waterproof Function(3ATM): It can be used when rainy and you are washing hands (without hot or warm water). CAN NOT be used when swimming or any other in-water activities. CAN NOT be closed with hot or warm water.