Casio has announced four G-Shock models in the G-Steel series that come with what the brand calls its "slimmest profile" yet.

They are each different variants of the GST-B400, coming with different colour schemes and finishes.

The case is just 12.9mm slim, with an improved module. This uses fewer components, which have also been modified to be smaller than previous G-Steel equivalents. The internal layout has also been optimised for a flatter footprint.

While not smart as such, each of the new models can be connected to a Smartphone by Bluetooth. The Bluetooth profile this time uses less power than before, with this generation of GST-B400 boasting lower power consumption than the last overall - 55.7 per cent, claims Casio.

The Bluetooth connectivity enables each watch to automatically adjust time. A Time & Place function also gives the user control of the time and position on a map inside a dedicated app with just press of a button. There is also a reminder setting.

A phone finder feature is also built in, so you can press a button to locate your smartphone if lost.

As with other G-Shock watches, these four are shock resistant and water resistant to 200 metres. The standard GST-B400 comes with a resin band and is available in black. The GST-B400D is silver with a stainless steel band.

The GST-B400AD also comes in stainless steel, but is red and black. While the GST-B400BD has a darker stainless steel band and a blue face.

All four will be available from the official G-Shock online shop from 24 May 2021. General availability will be from June.