Casio G-Shock GA-B2100C-9AER – CasiOak with Tough Solar and Bluetooth, Yellow

The Casio G-Shock GA-B2100C-9AER represents the 'CasiOak' evolved—the beloved octagonal design now enhanced with Tough Solar charging and Bluetooth connectivity. That yellow case isn't subtle, and that's entirely intentional. This watch makes statement whilst delivering genuine technical capability. The 48.5mm case maintains wearable dimensions despite the bold colour, whilst the slim 11.9mm profile ensures this doesn't stand proud like typical oversized G-Shocks.

Tough Solar charging eliminates battery replacement concerns entirely. The solar cell harvests energy from any light source, storing surplus in rechargeable battery. This transforms the watch from battery-dependent device to genuinely sustainable timepiece. The Bluetooth link connects to smartphone for automatic time adjustment four times daily, easy function setting, and access to approximately 300 world time cities through the app.

The Carbon Core Guard structure protects the module with carbon fibre-reinforced resin case—strength and lightness without excessive bulk. The octagonal bezel inherited from the original DW-5000 creates instant recognition. The dual-layer dial construction adds depth to the analogue-digital display, whilst the LCD subdial shows function modes and battery level rather than day of week.

Shock resistance handles the impacts that destroy conventional watches. Water resistance to 200 metres covers serious swimming, snorkelling, and water sports. The mineral glass resists scratches from rocks, walls, and daily abuse. Weight stays at 52 grams—remarkably light for G-Shock capability. The Super Illuminator LED provides brilliant illumination for both analogue and digital displays.

Functions include world time, stopwatch with 1/100-second accuracy, countdown timer, five daily alarms. The perpetual calendar runs until 2099 without adjustment. Phone finder locates misplaced smartphone. The resin band handles sweat, saltwater, and rapid cleaning without degradation.

This GA-B2100C-9AER serves anyone who wants G-Shock protection with modern connectivity and solar sustainability. The yellow colourway makes bold statement, whilst the enhanced features justify the premium over simpler G-Shock models. Casio's proven that tough watches can also be technically sophisticated—this CasiOak exemplifies that evolution brilliantly.