Small active piezo buzzers 5v and 12v

Hi, I needed 2 small buzzers for my 2 projects. First I did mistake and bought passive buzzer where I need PWM signal. Later I ordered two packages more, 5V and 12V but I mixed them up and they look the same. Here is a pic on how they look: https://ae01.alicdn.com/kf/HTB1itf_GVXXXXa_aXXXq6xXFXXXm/220878921/HTB1itf_GVXXXXa_aXXXq6xXFXXXm.jpg

So I wanted to test them, so took 1 of each and first connected it to 5V, hmm sound was the same on both so I connected to 12V and it was completely the same, then I tested rest of them and all the same on both 5 and 12 only the sound volume is higher at 12V. Does it mean that those small buzzers are all the same? Or eventually those 5V will burn when powered with 12V? or they are something like those bigger buzzzers 3V-25V?

Can I somehow distinguish them now?

Or eventually those 5V will burn when powered with 12V?

Yes that will happen.

If one pulls more current at 5V, then its probably the 5V one.

Can I somehow protect it? Resistor? It is weird that there is completely no signs on the part what voltage it is. I have bigger piezo active buzzer and there I have 3-25V range, i thought they could be similar with voltage range.