If you want to access the QR code of your Check'In Pro 2, it is also located on its box.
If you want to access the IMEI of your sensor, it is available in the Check'In app in the Information tab, then Advanced Information.
To remove the Check'In Pro 2 from its support, you need to take out the SafeStick from the middle slot and place it in the top slot of the Check'In Pro 2.
You can use a paper clip or a pen tip to help with this.
Here is the procedure in video: