It's not loose, they are sturdy with strong magnetism and force of attraction, do not fall out, which helps keep the charger in place for reliable charging.
It can be connected to a USB power source on a PC, laptop, notebook because this charging method can provide high efficiency and high stability charging experience for you.
It provides fast and stable charging speed. Made of over-voltage and over-current protection, they will protect your watch from being damaged when charging.