With the new RF 45 Advanced Remote Sonar Sensor, you get even greater performance from your SmartCast wireless remote sonar: greater depth capability (120 feet); water surface temperature reading; longer in-the-water use (500 hours with the WetSwitch technology); programmable two-channel operation so you can fish with a buddy without crossing signals; and even a flashing, internal light for night fishing that you can switch on or off.