G-Shock's Mtgb3000D-1A, with a Carbon Core Guard structure combines with the Metal Core Guard structure to create a new Dual Core Guard structure, which houses a module protected by an integrated 51mm carbon monocoque case and stainless steel bracelet with deployment clasp. The New Layered Composite Bands of these models use hollow metal segments that encase fine resin parts, providing the elegant feel of metal along with weight that is 15% less than that of previous models. Function-wise, these models maintain constant Bluetooth connection with a smartphone running the G-Shock Connected app to obtain accurate time information from an on-line time server for automatic time adjustment, even if you move between time zones. Multiband 6 automatically adjusts time settings based on reception of one of six calibration signals around the globe when you are within the range of a signal.