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Sometimes you want a watch that you simply don't have to worry about. Whether you're hiking, climbing or even swimming, this Casio G-Shock proves it's a reliable companion for any of your adventures. This function-filled timepiece is capable of so much (just check out the list below for all the details). And with a cool bully bar adding even more protection for the case, there's no question this watch is ready for whatever you're planning for your next adventure.

  • Shock resistant
  • Luminescent backlight with afterglow
  • World timer
  • 1/100-second stopwatch, elapsed time, split time and countdown timer
  • Full auto-calendar
  • Five daily alarms

Watch Details

  • Movement: 3434 Quartz
  • Movement Country of Origin: China
  • Case Measurements: 48mm
  • Thickness: 19mm
  • Case Material: Resin
  • Bezel: Fixed
  • Crystal: Mineral
  • Crown: Function pushers
  • Strap: Resin
  • Strap Measurements: 9-1/2" L x 24mm W
  • Clasp: Buckle
  • Maximum Wrist Size: 8-1/2"
  • Water Resistance: 20 ATM - 200 meters - 660 feet
  • Weight: 2.8 oz
  • Watch Country of Origin: China
  • Additional Information: Comes in Casio watch box with warranty information and instruction manual. 


  • One-year limited warranty provided by Casio. Please contact: 1-800-706-2534

Please see the Details tab to view the model number.

Check out the Watch Sizing Guide to view the actual case size.

Model Number GD-400MB-1

Chronograph: Functioning similarly to a stopwatch, a chronograph is a unique and valued complication due to its ability to measure increments of elapsed time while the watch still maintains traditional timekeeping abilities. The crown controls the analog watch while function pushers allow you to start, stop and reset the chronograph subdials. Variations of chronographs include the double chronograph with two separate stopwatch mechanisms and the flyback chronograph which allows the user to stop, reset and start the chronograph with a single depression of the function pusher.

Quartz: Although not as mechanically complex as other engines, the quartz movement provides the most accurate and reliable time-keeping. This type of movement typically draws power from a battery and centers around a small vibrating chip of quartz crystal. When an electrical current, supplied from a battery, is applied to a quartz crystal, the current is distorted and creates a precise resonating frequency. Watchmakers employ the subsequent frequency to measure time. Some adaptations to the traditional quartz movement include introducing rotors and power cells in an effort to maintain the accuracy of quartz while eliminating the need for a battery. Quartz movements have been used in timepieces since the 1970s and are highly accurate, dependable and affordable.

The case provides the foundation for all other major watch components. It houses the movement, maintains the lugs for attachment to the bracelet or strap, plays host to various crowns and function pushers, and seats the crystal and bezel.

Cases exist in a variety of shapes and sizes and utilize a library of materials for construction such as stainless steel, gold, ceramic, titanium, plastic, and more. The dominance of stainless steel in case construction remains, however, hypo-allergenic metals and materials, like titanium, continue to gain in popularity. Metal cases often have particular finishes - such as a smooth reflective polish or circular matte brush - that enhance the presentation of the timepiece and give it unique depth.

Some designs allow for the case and lugs to be curved in order for the watch to have a more comfortable fit around the wrist. The back of a case will typically be removable and most likely be screw down or pop-off. It is important to note, however, it should only be opened by a trained professional. An exhibition feature (found within a case's back) refers to an added window that allows you to view the movement and is often found on automatic and mechanical timepieces.

Case Size:
Case measurements do not include crown or lugs.

  • Round - One measurement, 8:00 to 2:00
  • Square - One measurement, 3:00 to 9:00 or 6:00 to 12:00 (should be the same)
  • Rectangle, Tonneau, Oval, Octagon, etc. - Two measurements, 3:00 to 9:00 and 6:00 to 12:00
  • Watch Case Dimension Comparisons:
    It can be difficult to determine how a watch will fit on your wrist without trying it on first. Get a better feel for the size of a watch case by comparing the case diameter to the following diameters of common objects:
  • Nickel: 21.21mm
  • Quarter: 24.26mm
  • Half Dollar: 30.61mm
  • Poker Chip (standard): 39mm
  • Ping Pong Ball: 40mm
  • Golf Ball: 42.67mm
  • Tow Ball Hitch (ISO standard): 50mm
  • Racquetball: 57mm
  • Soda Can (standard): 65mm
  • Tennis Ball: 67mm

  • About the Collection:

    Experience the rugged style and performance of Casio®, one of the world's most iconic watch brands. Casio watches are designed for active lifestyles; many include advanced timing and measurement capabilities such as self-adjusting atomic timekeeping, altimeters, barometers and more.

    In 1983, Casio launched the shock-resistant G-SHOCK watch. This product shattered the notion that a watch is a fragile piece of jewelry that needs to be handled with care. Since, Casio has expanded its assortment, creating designs for every activity, purpose and style.

    In addition to G-Shock, Casio is known for its highly detailed, sport-focused Ediface collection, as well as their tough, digital Pro-Trek designs. By employing the latest digital and analog technologies into their timepieces, Casio continues to transcend conventional watch design. Invite Casio, the ultimate in tough, reliable timekeepers on your next adventure.