Precautions During Use

Display Information Accuracy

Tide Graph Precautions

For Japan area oceans, tide times and level changes are predictively calculated using harmonic constant data obtained from Bibliography 742 Tidal Harmonic Constants Tables, Japanese Coast (February 1992) published by the Hydrographic Department of the Japan Coast Guard, and from the List of Tidal Stations (2015) published by the Japan Meteorological Agency. For other area oceans, tide times and level changes are predictively calculated using harmonic constant data obtained from NOAA, NOAA CO-OPS, and the NOAA Tides & Currents website.

Actual tidal phenomena fluctuate in accordance with weather, the season, and various other factors, and may give rise to irregularities not in accordance with calculated values. Certain conditions may result in actual tides being more than one hour different from calculated data. Because of this, the information produced by the Tide Graph function of this app and watch should be treated as approximate reference information only. Never use it for navigation or any other decisions about tide that may put safety at risk.

Sunrise/Sunset Precautions

Sunrise and sunset calculations are performed using the following azimuths: North: 0 degrees, East: 90 degrees, South: 180 degrees, West: 270 degrees. Calculation results include error of multiple seconds, and error becomes greater at higher latitudes. Calculations assume a level horizon, and local topography is not taken into consideration.

Moon Age Precautions

Moon ages displayed by this watch are based on the calculation described below.
(1) Elongation is calculated using solar and lunar coordinates produced by functional calculus.
(2) Moon age is calculated based on the correlation between the elongation and average moon age.
Though the lunar period averages 29.53 days, it actually fluctuates by as much as ±1 day, so this calculation produces an error of up to ±1 day.

Water Resistance

This watch is water resistant up to five atmosphere, which means it can be worn while working around water and while swimming. However, note the information below.

  • Even if a watch is water resistant, note the usage precautions described below.
  • Avoid using this watch while windsurfing, skin diving, or scuba diving.
  • Do not operate the buttons while your watch is submersed in water or wet.
  • Do not charge the watch while it is in water or wet.
  • Avoid wearing your watch while in the bath.
  • Do not wear your watch while in a heated swimming pool, sauna, or any other high temperature/high humidity environment.
  • Do not wear this watch while washing your hands or face, or while performing any other task that includes the use of soap or detergent.
  • The touch screen does not work while the watch is submerged in water.
  • After submersion in seawater, use plain water to rinse all salt and dirt from your watch.
  • To maintain water resistance, have the gaskets of your watch replaced periodically (about once every two or three years).
  • Be sure to leave battery replacement up to an authorized CASIO service center or your original retailer. Unauthorized battery replacement may cause problems with the waterproof performance of the watch.
  • The inside surface of the watch glass may fog when the watch is exposed to a sudden drop in temperature. No problem is indicated if the fogging clears up relatively quickly. Sudden and extreme temperature changes (such as coming into an air conditioned room in the summer and standing close to an air conditioner outlet, or leaving a heated room in the winter and allowing your watch to come into contact with snow) can cause it to take longer for glass fogging to clear up. If glass fogging does not clear up or if you notice moisture inside of the glass, immediately stop using your watch and take it to an authorized CASIO service center or to your original retailer.
  • Do not charge the watch if the watch or charger cable is wet. Wipe off all moisture and make sure the watch and charger cable are dry before charging.


This watch has been tested for the items described below in accordance with the MIL-STD-810G standard established by the U.S. Department of Defense.

  • Shock resistance is based on the assumption of normal daily use. Throwing the watch, or subjecting it to excessive dropping or other extreme shock can cause it to break.
  • Be sure to read the information in this manual under Precautions During Use and User Maintenance in order to ensure proper use of this watch. Failure to use the watch in accordance with this information creates the risk of overheating, fire, electric shock, personal injury, and accident.
  • The functions of this watch have been confirmed under test environments, but no guarantees are made concerning operation under all environments where it may be used. Also, no guarantees are made concerning the ability of the watch to withstand damage or malfunction.


Tested in accordance with Method 516.7 Procedure IV.


Tested in accordance with Method 514.7 Procedure I.


Tested in accordance with Method 507.6 Procedure II.

Solar Radiation

Tested in accordance with Method 505.6 Procedure II.

Low Pressure Storage

Tested in accordance with Method 500.6 Procedure I.

Low Pressure Operation

Tested in accordance with Method 500.6 Procedure II.

High Temperature Storage

Tested in accordance with Method 501.6 Procedure I.

Low Temperature Storage

Tested in accordance with Method 502.6 Procedure I.

Thermal Shock

Tested in accordance with Method 503.6 Procedure I-C.


Tested in accordance with Method 521.4 Procedure I.

Protective stickers

  • Be sure to remove all protective stickers and/or paper tags that may be affixed to your watch (including its back cover) and/or its band when you purchase it. Using the watch without removing protective stickers and/or paper tags may result in the build-up of dirt between the watch/band and the sticker/paper tag, which creates the risk of rust and skin rash.


  • The watch and AC adaptor may become warm to the touch during charging. This is normal and does not indicate malfunction.
  • Do not charge the watch in a location where large amounts of moisture, dust, or fine metal particles are present, in a location subjected to vibration, or near a hard line telephone, a TV, a radio, etc.
  • The charger cable of this watch is magnetic. Contact with sand containing iron particles can make it unusable for charging. Should the charger terminal or cable become soiled with mud or sand, thoroughly wipe off all foreign matter before charging.
  • In an area where it is extremely cold or hot, you may not be able to charge the watch or the watch may not charge completely. Charge the watch in an area where the ambient temperature is between 10°C and 35°C (50°F and 95°F).


  • Tightening the band too tightly can cause you to sweat and make it difficult for air to pass under the band, which can lead to skin irritation. Do not fasten the band too tightly. There should be enough room between the band and your wrist so you can insert your finger.
  • Deterioration, rust, and other conditions can cause the band to break or come off of your watch, which in turn can cause band pins to fly out of position or to fall out. This creates the risk of your watch falling from your wrist and becoming lost, and also creates the risk of personal injury. Always take good care of your band and keep it clean.
  • Immediately stop using a band if you ever notice any of the following: loss of band flexibility, band cracks, band discoloration, band looseness, band connecting pin flying or falling out, or any other abnormality. Take your watch to an authorized CASIO service center or to your original retailer for inspection and repair (for which you will be charged) or to have the band replaced (for which you will be charged).


  • Never leave your watch on the dashboard of a car, near a heater, or in any other location that is subject to very high temperatures. Do not leave your watch where it will be exposed to very low temperatures. Doing so can cause malfunction.
  • Leaving your watch in an area hotter than +60°C (140°F) for long periods can lead to problems with its LCD. The LCD may become difficult to read at temperatures lower than 0°C (32°F) and greater than +40°C (104°F). Watch operation that is stopped due to high temperatures will not resume until watch cools sufficiently. Wait for a while to allow the watch to cool.


  • Some watch functions may not operate normally in a location where magnetism is present. Very strong magnetism (from medical equipment, etc.) should be avoided because it can cause malfunction of your watch and damage to electronic components.


  • Do not allow your watch to come into contact with thinner, gasoline, solvents, oils, or fats, or with any cleaners, adhesives, paints, medicines, or cosmetics that contain such ingredients. Doing so can cause discoloration of or damage to the resin case, resin band and other parts.


  • If you do not plan to use your watch for a long time, thoroughly wipe it free of all dirt, sweat, and moisture, and store it in a cool, dry place.
  • Disconnect the charger cable from the AC adaptor when not charging. The charger cable is magnetic, so keep it away from magnetic cards, precision equipment, and analog watches.

Resin Components

  • Allowing your watch to remain in contact with other items or storing it together with other items for long periods while it is wet can cause color on resin components to transfer to the other items, or the color of the other items to transfer to the resin components of your watch. Be sure to dry off your watch thoroughly before storing it and make sure it is not in contact with other items.
  • Leaving your watch where it is exposed to direct sunlight (ultraviolet rays) for long periods or failure to clean dirt from your watch for long periods can cause it to become discolored.
  • Friction caused by certain conditions (strong external force, sustained rubbing, impact, etc.) can cause discoloration of painted components.
  • If there are printed figures on the band, strong rubbing of the printed area can cause discoloration.
  • Daily use and long-term storage of your watch can lead to deterioration, breaking, or bending of resin components. The extent of such damage depends on usage conditions and storage conditions.

Watch Sensors

  • A watch sensor is a precision instrument. Never try to take it apart. Never try to insert any objects into the openings of a sensor, and take care to ensure that dirt, dust, or other foreign matter does not get into it. After using your watch where it has been immersed in saltwater, rinse it thoroughly with fresh water.

Metal Components

  • Failure to clean dirt from metal components can lead to formation of rust, even if components are stainless steel or plated. If metal components exposed to sweat or water, wipe thoroughly with a soft, absorbent cloth and then place the watch in a well-ventilated location to dry.
  • Use a soft toothbrush or similar tool to scrub the metal with a weak solution of water and a mild neutral detergent, or with soapy water. Next, rinse with water to remove all remaining detergent and then wipe dry with a soft absorbent cloth. When washing metal components, wrap the watch case with kitchen plastic wrap so it does not come into contact with the detergent or soap.

Liquid Crystal Display

  • Display figures may be difficult to read when viewed from an angle.
  • The LCD of this watch has flat bottom, and so it is not round. Because of this using a watch face that is designed for a round display may result in some part of the face being cut off.
  • The liquid crystal panel of this watch uses high-precision technology that provides a pixel yield in excess of 99.99%. This means that some very small number of pixels may not light or may remain lit at all times. This is due to the characteristics of the liquid crystal panel, and does not indicate malfunction.