Last year Casio G-Shock introduced some its most tech-savvy releases to date with the debut of Bluetooth technology for its timepieces. Now the brand is set to introduce the latest iteration: the GB-X6900B. Essentially a beefed-up take on the much-loved DW-6900, the design incorporates Bluetooth v4.0 and boasts a new 2.0 engine that allows for two-way communication between the watch and your smartphone via a free app. Thus, your watch can be used for everything from operating music playback and setting alarms to receiving email and call notifications. Due to be available come September 21, a trio of colorways will drop for ¥20,000 JPY (approximately $208 USD) each with compatibility offered via the iPhone 5, iPhone 4S and Samsung Galaxy S4.