This is the sophisticated Casio G Shock G Steel Silver and Black Watch GST B400D 1ADR with a stainless steel construction. Introducing new color variations to the lineup of slim G STEEL GST B400 models with new, improved designs made possible by a thin module and carbon core guard structure. There is a standard model in this lineup, the GST B400 with silver color face and resin band. The GST B400 is made possible by even further miniaturization of its parts and thinning of its modules without sacrificing any Bluetooth or solar function. Power consumption has also been significantly reduced.