When in use, a compatible Samsung Galaxy device acts as the headset's display and processor, while the Gear VR unit itself acts as the controller, which contains the high field of view, as well as a custom inertial measurement unit, or IMU, for rotational tracking, which connects to the smartphone via micro-USB. This IMU is more accurate and well calibrated with lower latency than internal smartphone IMUs, such as those used for Google Cardboard.