Portable charger reconmendation please

[Damonlufc88]

Hi. I have a Sony xz phone and want a portable charger. I've looked at the one below but I don't understand what the 5000 mAh means and there are different varieties on the website listed. It's usb universal I just want to know its not going to fry my battery

https://www.argos.co.uk/product/6227605