Citizen Caliber U010: Eco-Drive Analog-Digital Movement With Dive Function, Depth Meter, and Chronograph

The Citizen Caliber U010 is a multifunctional Eco-Drive movement that integrates both analog and digital displays to deliver a wide range of professional-grade features. Designed especially for diving and aquatic environments, this movement powers watches that include depth sensors, chronographs, alarms, and dive memory, all while running solely on light energy.

This caliber is featured in models from Citizen’s Promaster Aqualand line and is considered one of the most advanced solar-powered movements tailored for underwater use.

Core Features

The U010 is packed with functions to support underwater and everyday operations:

• Eco-Drive powered: No battery replacement required

• Analog timekeeping: Hour, minute, second hands

• Digital display: LCD for auxiliary functions

• Dive mode: Auto-activated by water depth

• Depth meter: Measures from 1.0 m to 80.0 m (with increments of 0.1 m)

• Dive timer: Automatically records dive start/end and max depth

• Log memory: Stores up to 20 previous dive records

• Chronograph: Measures up to 99 hours, 59 minutes, 59 seconds

• Timer: Countdown timer function

• Alarm: Daily alarm with sound

• Calendar: Digital day/date display with automatic calendar correction

• Backlight: For nighttime or underwater viewing

• Water temperature measurement

• Low charge indicator: Second hand moves in 2-second intervals

• Power reserve: ~6 months (can extend with power save)

These features make the U010 an ideal companion for both professional divers and adventure sports enthusiasts.

Eco-Drive Solar Charging System

The U010 uses Citizen’s signature Eco-Drive technology, which charges the internal energy cell via natural or artificial light.

Charging Capabilities:

• Full charge runtime: Approximately 6 months

• Power save mode: Extends up to 2 years

• Recharge times:

  • Full sunlight: ~8–12 hours to full charge

  • Office lighting: ~100+ hours

• Charging indicator: Low power is signaled by a skipping second hand (2-second intervals)

With Eco-Drive, users never need to replace a battery, making this movement highly sustainable and perfect for long-term use in remote or underwater locations.

Dive Functionality

One of the key highlights of the U010 is its diving utility, which activates automatically once the watch detects submersion:

• Activation threshold: ~1 meter underwater

• Depth tracking: From 1.0 m to 80.0 m

• Dive timer: Automatically logs dive duration and maximum depth

• Memory: Stores up to 20 dive records including:

  • Date of dive

  • Start time

  • Duration

  • Maximum depth

• Water temperature: Measured during each dive

• Display lockout: Analog hands may shift out of the way for better digital screen visibility

This movement complies with ISO 6425 dive watch standards when installed in certified watch cases.

Chronograph and Timer Functions

• Chronograph:

  • Digital stopwatch mode

  • Maximum duration: 99:59:59 (hh:mm:ss)

  • 1-second resolution

• Countdown Timer:

  • Settable from 1 minute to 99 hours

  • Audible signal at timer end

Both are controlled via designated pushers, with timing visible in the digital screen.

Alarm and Calendar

• Alarm:

  • One daily alarm

  • Clear audible tone

  • Configured via digital interface

• Calendar:

  • Fully automatic

  • Displays day and date

  • Adjusts for leap years

Operation and Controls

The U010 uses a combination of a crown and three pushers, typically laid out as follows:

1. Mode button: Cycles through TIME, DIVE, CHRONO, TIMER, ALARM, LOG

2. Set/Adjust: Used for time, alarm, and other settings

3. Start/Stop and Reset: Controls for chronograph and timers

4. Backlight: Activated with long press or designated button

The analog hands work independently but in sync with the digital functions for real-time reference.

Watch Applications and Design

Watches equipped with the U010 movement are:

• Part of the Promaster Aqualand family

• Designed for divers, rescue workers, and sports adventurers

• Feature robust stainless steel or titanium cases

• Include screw-down crowns, unidirectional bezels, and sapphire or mineral crystals

• Offer water resistance of 200M or more

• Typically sized at 44–48 mm, optimized for underwater legibility

Straps are often rubber or polyurethane to withstand saltwater and pressure.

Maintenance and Durability

• No battery replacement ever (Eco-Drive system)

• Regular light exposure keeps it charged

• Gasket checks every few years for water resistance

• Sensor and crown cleaning recommended after saltwater use

This movement is designed for decades of functional use in the harshest conditions.

Ideal Users

The U010 movement is best for:

• Scuba and free divers

• Water sports professionals

• Adventurers and explorers

• Eco-conscious watch users

• Collectors of multi-function dive watches

Summary

The Citizen Caliber U010 is a powerful, feature-rich Eco-Drive analog-digital movement designed specifically for diving and high-performance use. With a depth meter, dive memory, solar charging, and full chronograph/alarm functionality, it offers everything a diver or outdoor enthusiast needs—with zero battery hassle. Durable, smart, and endlessly functional, the U010 is a true tool watch engine for those who live life below the surface or on the edge.