G-Shock Watch G-Steel Mens GST-B400CD-1A3ER. The GST-B400 with popular Green Bezel colour. Innovative thin modules, carbon core guard structures, and miniaturization of many working parts help to make it the thinnest of the G-STEEL Series while maintaining a high level of impact resistance and without sacrificing any Bluetooth or solar functions. Power consumption has also been significantly reduced. In terms of design, the number of button guards has been reduced as much as possible, enabling the use of large stainless steel buttons that are slim yet easy to operate. The top bezel has been given five different finishes, while the middle bezel has been given four different finishes, which creates an elegant effect and changes the appearance of the texture of the metal depending on the viewing angle. Functions include 5 alarms, a stop watch, timer and double LED light.