Citizen Eco-Drive BN2031-85E Instruction Manual page 23

Water depth measurement
Starting measurement
This watch automatically starts water depth measurement as the wearer enters the
water.
E
Power reserve
indication hand
22
Water sensor
When the water sensor is in
contact with water for about
2 seconds, the power reserve
indication hand points to
"READY" and the water
pressure sensor starts water
depth measurement.
Crown