Watch Gravitymaster GR-B300-8A2ER

The Watch

Casio keeps pushing boundaries, crafting timepieces that are as tough as they are reliable. The brand offers a wide range of fully equipped watches engineered to handle demanding - even extreme - conditions. With a distinguished expertise, the Japanese watchmaker creates models for every enthusiast, from everyday classics to hard-core sport editions. Discover the Gravitymaster GR-B300-8A2ER - a watch built for all. Its round case is crafted from bio-based resin reinforced with carbon fiber, delivering exceptional rigidity and resistance to shocks and corrosion. In gray, the case measures 59 mm in length, 54.70 mm in width, 15.70 mm in thickness, and weighs 71 g. Its fixed bezel stamped with "G-Shock" and "Protection" is made from the same materials and features a minute scale. It surrounds the mineral glass that sits above the dial. At 3 o'clock, a gray screw-down crown with a knurled grip ensures a firm hold. This crown, together with the 4 pushers around it, controls the watch's various functions. The case is sealed by an engraved caseback secured with screws, ensuring a water resistance of 20 ATM.

The Dial

This dial is beautifully laid out for a comfortable and accurate time reading. Its gray base is elevated by a sandblasted finish that gives it a satin-like look. Featuring an LED backlight that illuminates it for approximately 1.5 seconds, it presents a bezel ring with a minute track and bicolor hour markers. At its center, three hands tell the time with precision: a short hour hand, a long minute hand, and a slim blue seconds hand. All hands are treated with a Neobrite coating for enhanced readability in the dark. At 3 o'clock, a date window sits alongside additional sub-dials at 4, 6, 9, and 12 o'clock with multiple functions. The first sub-dial - the smallest - features a small blue hand pointing toward A or P to indicate AM or PM. The second displays the second time zone in 12-hour format. The third sub-dial shows the battery level, and the last one displays the day of the week, alarm (AL), timer mode (TR), and stopwatch mode (ST). Note that the seconds hand also moves for certain functions: it rotates toward (C) for Bluetooth connection or (R) for connection standby, points to (A) for AM or (P) for PM, and to (ON)/(OFF) for alarm activation or deactivation. Finally, the brand signs its name, movement type, and collection name near 3 o'clock.

Features

Time setting

Bluetooth: connects to a smartphone and automatically sets the time

Power supply and battery life

Tough Solar (solar powered)

Smartphone Link feature

Mobile Link (wireless linking via Bluetooth®)

Apps

CASIO Watches

App connectivity feature

Automatic time adjustment

Easy watch setting

300 world time cities

Flight log

Phone finder

World Time

Second time zone (home city time change)

Stopwatch

1-second stopwatch

Measuring capacity: 23:59'59.

Measuring modes: elapsed time, split time

Timer

Countdown Timer

Measuring unit: 1 second

Countdown range: 24 hours

Countdown start time setting range: 1 minute to 24 hours (1-minute and 1-hour increments)

Alarm/time signal

Daily alarm

Lighting

LED lighting (Super Illuminator)

Afterglow

Light color

LED: white

Calendar

Full auto-calendar (until the year 2099)

Power saving function

Power saving (hands stop to conserve energy when the watch is left in the dark)

Battery level display/alert

Battery level indicator

The Movement

This timepiece runs on a reliable, precise solar movement. Of Japanese origin, this mechanism delivers accuracy to within ±15 seconds per month (without the Mobile Link function). It features an integrated solar panel built into the dial that easily recharges the battery using natural or artificial light. The battery offers an energy reserve of approximately 5 months without light exposure after a full charge.

The Strap

This strap delivers a secure and comfortable fit. In gray, it is crafted from bio-based resin for outstanding durability and flexibility. It features textured, raised patterns and hugs the contours of your wrist effortlessly. It also comes with a double-lock pin buckle for easy adjustments and fits wrist circumferences from 145 to 215 mm.

Water Resistance

This model offers a water resistance of 20 atmospheres, or 200 meters. Ladies and gentlemen, this is a watch built for serious underwater adventures - it's designed for freediving! Rain, splashes, high-pressure washers, showers, baths, lap swimming, and breath-hold diving are all no match for this timepiece. However, for scuba diving with tanks, we recommend a timepiece with a higher water resistance rating. Also, avoid operating the crown or pushers while submerged to protect the movement's integrity.