Hubsan X4 is a nice quadcopter that is great for learning to fly a RC model. It is also a nice way to relax on your break since it can be flown inside. Its battery life is not so great so you'll need couple of batteries if you want to prolong your enjoyment.
Batteries are a little hard to remove after a flight since they get hot and grow in size which is normal , however please note that if you're battery is too puffy – it's time to replace it , it might not be safe ! Pulling the battery by its leads is not safe and can tear off the leads or damage the protection PCB and/or battery.
This video shows how to remove the battery first time without damaging it and then (most important) shows you a little trick how to make the future battery replacements a snap !
Your tips and comments are welcome, also let me know if this helped you