Casio G-SHOCK GA-2100K Series Analogue Digital Watch (GA-2100K-5AER)

Overview

The Casio G-SHOCK GA-2100K-5A delivers a distinctive interpretation of the iconic octagonal G-SHOCK 2100 Series, combining contemporary design with the exceptional toughness that has defined G-SHOCK for decades. Inspired by the atmospheric lighting and vibrant energy of music festivals and nightlife, this analogue-digital watch features a smoky translucent brown case and strap, a deep piano-black dial and striking neon red accents that create a bold contrast against its understated colour palette.

Beyond its distinctive appearance, the GA-2100K-5A incorporates Casio's advanced Carbon Core Guard construction, providing dependable shock resistance in a lightweight, slim-profile design. With 200-metre water resistance, dual LED illumination, World Time functionality and a comprehensive range of timing features, it delivers the reliability and versatility expected from a professional-quality G-SHOCK. Weighing just 51 g and measuring only 11.8 mm thick, it offers exceptional comfort for everyday wear, outdoor activities and demanding environments.

Key Features

• Iconic octagonal G-SHOCK 2100 Series design
• Smoky translucent brown resin bezel and strap with a distinctive matte finish
• High-gloss piano-black dial with contrasting neon red accents
• Nightlife-inspired design influenced by laser lighting, smoke and music festivals
• Newly developed smooth dial surface for a refined, contemporary appearance
• Carbon Core Guard structure for lightweight shock resistance
• 200-metre water resistance for swimming and outdoor activities
• Analogue-digital display with separate day indicator
• Double LED Super Illuminator for enhanced visibility in darkness
• World Time covering 31 time zones and 48 cities, plus UTC
• 1/100-second stopwatch with split-time measurement
• 24-hour countdown timer for training and everyday timing tasks
• Five daily alarms and optional hourly time signal
• Hand Shift function for improved digital display visibility
• Neobrite luminous coating for low-light time reading
• Approximately three-year battery life
• Lightweight 51 g construction with a slim 11.8 mm case

Specifications

• Model: GA-2100K-5A
• Collection: G-SHOCK 2100 Series
• Display: Analogue and digital
• Case Dimensions: 48.5 × 45.4 × 11.8 mm
• Weight: 51 g
• Case & Bezel Material: Carbon / resin
• Case Colour: Translucent brown
• Dial Colour: Piano black with neon red accents
• Strap: Matte translucent brown resin band
• Compatible Wrist Size: 145–215 mm
• Glass: Mineral glass
• Construction: Shock Resistant, Carbon Core Guard
• Water Resistance: 200 metres (20 bar)
• Power Source: Two SR726W batteries
• Battery Life: Approximately 3 years
• Timekeeping Accuracy: ±15 seconds per month
• Illumination: Double white LED Super Illuminator
• Additional Features: Neobrite, Hand Shift and full auto calendar
• Country of Manufacture: Thailand

Smoky Translucent Design with Neon Red Accents

The GA-2100K-5A stands apart from conventional G-SHOCK models through its distinctive combination of transparency, texture and colour. Drawing inspiration from the atmosphere of late-night music venues, its translucent brown resin case and strap recreate the smoky, diffused appearance of light passing through a haze-filled environment.

The matte exterior provides a subtle contrast against the deep, glossy piano-black dial. Casio's newly developed dial surface creates a smooth, refined finish that enhances the richness of the black background, while vivid neon red accents evoke the appearance of laser beams cutting through darkness.

This carefully considered combination of materials and finishes creates a watch that feels both contemporary and unmistakably G-SHOCK. The warm brown translucent construction offers a distinctive alternative to traditional solid black or brightly coloured resin watches, making the GA-2100K-5A particularly appealing to users who appreciate technical design with a strong visual identity.

Carbon Core Guard Protection

At the heart of the GA-2100K-5A is Casio's Carbon Core Guard structure, which uses carbon fibre-reinforced resin to protect the internal watch module against shocks and impacts. This advanced construction combines strength with reduced weight, allowing the watch to maintain its slim proportions without compromising the durability expected from G-SHOCK.

The reinforced case provides dependable protection against the knocks and vibrations encountered during everyday activities, while the flexible resin strap ensures a comfortable fit throughout extended periods of wear. At just 51 g, the GA-2100K-5A offers impressive toughness without the bulk associated with larger sports watches.

Its 200-metre water resistance provides additional versatility, making the watch suitable for swimming, wet weather and demanding outdoor conditions. Combined with durable mineral glass and G-SHOCK's shock-resistant construction, it offers a practical balance of protection, comfort and reliability.

Analogue-Digital Timekeeping

The GA-2100K-5A combines the traditional readability of analogue hands with the functionality of a digital watch. Its two central hands provide clear hour and minute indications, while a separate day indicator and integrated digital display allow users to access additional information without compromising the clean appearance of the dial.

The Hand Shift function temporarily moves the analogue hands away from the digital display when they obstruct important information. This practical feature ensures that stopwatch readings, timer settings and other digital functions remain accessible when required.

World Time functionality covers 31 time zones across 48 cities, plus Coordinated Universal Time (UTC), with selectable daylight saving settings. This makes the watch useful for international travel, coordinating activities across different regions and monitoring time differences.

Double LED Super Illuminator

The GA-2100K-5A features Casio's Double LED Super Illuminator system, providing dedicated white LED illumination for both the analogue dial and digital display. This dual-light arrangement improves visibility in low-light environments, allowing users to check the time and operate digital functions after dark.

Both illumination systems offer selectable 1.5-second or 3-second lighting durations with afterglow. Neobrite luminous coating provides additional support for reading the analogue hands following exposure to light.

Whether working in poorly illuminated environments, travelling at night or enjoying outdoor activities after sunset, the combination of LED illumination and luminous detailing helps maintain practical timekeeping visibility.

Watch Features & Functions

• World Time: 31 time zones covering 48 cities plus Coordinated Universal Time (UTC), with daylight saving on/off settings.
• Stopwatch: 1/100-second measurement for the first 60 minutes, switching to one-second measurement thereafter, with a maximum measuring capacity of 23 hours, 59 minutes and 59 seconds.
• Stopwatch Modes: Elapsed time, split time and first/second-place finish times.
• Countdown Timer: Adjustable from one second to 24 hours, with one-second, one-minute and one-hour setting increments.
• Daily Alarms: Five independent daily alarms for reminders and scheduled activities.
• Hourly Time Signal: Optional audible alert every hour.
• Double LED Light: Separate white LED illumination for the analogue dial and digital display, with selectable 1.5-second or 3-second duration and afterglow.
• Hand Shift: Temporarily moves the analogue hands away from the digital display for improved visibility.
• Full Auto Calendar: Automatically adjusts the date through to 2099.
• Time Format: Selectable 12 or 24-hour digital display.
• Button Tone: Option to enable or disable button operation sounds.
• Analogue Display: Hour and minute hands, with the minute hand advancing every 20 seconds, plus a dedicated day indicator.
• Digital Display: Hours, minutes, seconds, AM/PM, month and date.

Lightweight Durability for Everyday Wear

Despite its bold appearance, the GA-2100K-5A remains a practical everyday watch. Its slim 11.8 mm case sits comfortably on the wrist, while the lightweight resin construction reduces bulk during extended wear. The flexible strap accommodates a wide range of wrist sizes and provides a secure fit during daily activities.

The combination of Carbon Core Guard protection, 200-metre water resistance and reliable battery-powered operation makes it well suited to users who want a durable watch without the need for frequent charging or complicated maintenance.

Powered by two SR726W batteries, the GA-2100K-5A provides approximately three years of operation under normal conditions. Its straightforward analogue-digital interface offers quick access to essential timekeeping functions, making it a dependable choice for work, travel, training and everyday use.

Why Choose the Casio G-SHOCK GA-2100K-5A?

The GA-2100K-5A combines the unmistakable octagonal design of the G-SHOCK 2100 Series with a distinctive colourway inspired by the energy and atmosphere of nightlife. Its smoky translucent brown case and strap, glossy piano-black dial and vivid neon red accents create a striking aesthetic that sets it apart from conventional G-SHOCK models.

Beyond its appearance, the watch delivers the proven performance that has made the 2100 Series so popular. Carbon Core Guard construction, 200-metre water resistance, double LED illumination and comprehensive timekeeping functions provide dependable versatility, while its lightweight 51 g construction ensures comfortable everyday wear. For anyone seeking a G-SHOCK that combines distinctive design with practical durability, the GA-2100K-5A offers an excellent balance of style, comfort and reliability.

Authorised Casio Retailer

TacTree is an authorised Casio UK retailer. All Casio watches supplied are 100% genuine, brand new and sourced through approved UK distribution channels. Orders are supplied with official Casio packaging and manufacturer documentation for complete authenticity and peace of mind.