Casio Japan, known for its calculators and wristwatches, has just introduced the first watches with Bluetooth LE (low energy) onboard, making it compatible with Bluetooth 4.0 cellphones like the iPhone 4S. The G-Shock GB-6900 will synchronize the current time from paired handsets and will display incoming call names or numbers, e-mails, and text messages on its display. Users can also switch handsets into vibration mode without touching them.