Casio is expanding its G-SHOCK G-STEEL line with two models that swap the metal bracelet for a resin band. They are the GST-B1000-1AJF and the GST-B1000-2AJF, both scheduled for release in August 2026. The GST-B1000-1AJF carries a suggested retail price of 60,500 yen including tax. The pair shares its core design with the metal-bracelet GST-B1000 series introduced last autumn, but drops the weight to 58 grams.

From 118 g to 58 g, with comfort as the priority

The GST-B1000 is a newer G-STEEL series that carries over the bezel shape and brick-pattern dial texture of the original 1983 G-SHOCK, the DW-5000C, while stripping the logo from the bezel for a more minimal look. The two new references are variants in which the stainless steel bracelet is replaced by resin.

The case measures 46.9 × 44.2 × 11.6 mm and weighs 58 g. Against the 118 g of the metal-bracelet version, that is a 60 g difference, and it changes how the watch feels on the wrist. A metal bracelet is often chosen for how it looks and feels in the hand, but the weight and the way it presses against the wrist can get in the way of daily wear. The resin-band models make a clear trade in the other direction.

The band accommodates wrist sizes from 145 to 215 mm. Stainless steel remains on the bezel, so these are not stripped-down budget versions: they combine a metal face with the lightness of resin.

Tough Solar and Bluetooth carry over unchanged

The feature set is inherited from the metal-bracelet models. Power comes from Tough Solar, a light-powered system designed to work without battery replacement. From a full charge with no further light exposure, the watch runs roughly 5 months with functions in use, or roughly 18 months in the power-saving state that halts the hands in the dark.

Timekeeping is corrected automatically over a Bluetooth link to a smartphone. The companion app, CASIO WATCHES, handles automatic time correction, watch settings, a Time & Place feature that stamps the date and location onto a map in the app at the press of a button, and a phone finder. Without a smartphone connection, the watch runs at standard quartz accuracy of plus or minus 15 seconds per month on average.

Other functions include a stopwatch that measures up to 30 minutes in 1-second increments, a timer of up to 30 minutes, a time alarm, a full auto calendar, and day and date display. In the dark, the Super Illuminator LED light comes on and includes an afterglow function. Neobrite is used on the hands.

Shock resistance and biomass plastic

The construction combines Casio's shock-resistant build with Carbon Core Guard. The case and bezel use carbon fiber reinforced resin together with stainless steel: the resin case protects the module while the metal on the outside absorbs impact. Water resistance is rated at 20 bar, the glass is mineral glass, and the crown is a screw-lock type.

The main resin parts of the case and band use biomass plastic, a material that includes renewable organic resources among its raw ingredients. Casio has been rolling it out broadly across recent G-SHOCK releases. It is not something you can identify by look or touch, but the switch has now reached the higher-end series as well.

Price gap and how to choose

The metal-bracelet GST-B1000D series sells for 66,000 yen. The gap to the 60,500 yen resin version is 5,500 yen, so price alone is not the deciding factor. The 60 g weight difference, and whether you want the watch to read as business-leaning or sporty, are what will actually settle the choice.

As for colors, the GST-B1000-1AJF has a black dial and the GST-B1000-2AJF a blue one. Both keep the red, blue and yellow accents inherited from the DW-5000C.

Summary

The GST-B1000-1AJF and GST-B1000-2AJF are lighter versions of the G-STEEL GST-B1000 with the bracelet replaced by resin. The case measures 46.9 × 44.2 × 11.6 mm and weighs 58 g, 60 g less than the metal-bracelet version. Tough Solar, Bluetooth connectivity, 20 bar water resistance and the Carbon Core Guard structure all carry over unchanged. The GST-B1000-1AJF is priced at 60,500 yen, with release set for August 2026.