Can I use the iPhone 5s charge case on my 4s without damaging it?

So I got the iPhone 5s charge case thingy. Can I use it on my iPhone 4s without damaging my 4s in any way. I tried it and the charger thing works. My 4s is a tiny bit tight. But when I turn the charging in it works. So will it damage it?

Yes you can. Apple built chargers that are more universal than ever for this very purpose. The size of the phone doesn't matter as long as the plug point and socket have the same voltage and amp specifications. Neither your 4s nor 5s are in any kind of danger or trouble. Have a hassle free charging experience. You're an apple customer. Its your right to be happy and tension free by default.

Only if you have the right adapter for it then it will work