diff --git a/include/mynteye/types.h b/include/mynteye/types.h
index da5f672..94cfff6 100644
--- a/include/mynteye/types.h
+++ b/include/mynteye/types.h
@@ -441,9 +441,11 @@ struct MYNTEYE_API ImgData {
  * IMU data.
  */
 struct MYNTEYE_API ImuData {
+  /** Imu serial number */
+  std::uint32_t serial_number;
   /** accel or gyro flag:1 for accel,2 for gyro,3 for both */
   std::uint8_t flag;
-  /** IMU timestamp in 0.01ms */
+  /** IMU timestamp in 1us */
   std::uint64_t timestamp;
   /** IMU accelerometer data for 3-axis: X, Y, Z. */
   double accel[3];
diff --git a/src/internal/motions.cc b/src/internal/motions.cc
index 3828b54..871cdde 100644
--- a/src/internal/motions.cc
+++ b/src/internal/motions.cc
@@ -47,18 +47,19 @@ void Motions::SetMotionCallback(motion_callback_t callback) {
         //     static_cast<uint32_t>(-seg.offset) > packet.timestamp) {
         //   LOG(WARNING) << "Imu timestamp offset is incorrect";
         // }
+        imu->serial_number = seg.serial_number;
         imu->timestamp = seg.timestamp;
         imu->flag = seg.flag;
         imu->temperature = seg.temperature / 326.8f + 25;
 
-        if(imu->flag == 1) {
+        if (imu->flag == 1) {
           imu->accel[0] = seg.aceel_or_gyro[0] * 12.f / 0x10000;
           imu->accel[1] = seg.aceel_or_gyro[1] * 12.f / 0x10000;
           imu->accel[2] = seg.aceel_or_gyro[2] * 12.f / 0x10000;
           imu->gyro[0] = 0;
           imu->gyro[1] = 0;
           imu->gyro[2] = 0;
-        } else if(imu->flag == 2) {
+        } else if (imu->flag == 2) {
           imu->accel[0] = 0;
           imu->accel[1] = 0;
           imu->accel[2] = 0;
@@ -68,7 +69,7 @@ void Motions::SetMotionCallback(motion_callback_t callback) {
         } else {
           imu->Reset();
         }
-        
+
         std::lock_guard<std::mutex> _(mtx_datas_);
         motion_data_t data = {imu};
         motion_datas_.push_back(data);