TIGHT CONNECTION DESIGN - 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 a reliable charging.<br />FAST CHARGE & STABLE PERFORMANCE - It can be connected to USB power source on PC, laptop, notebook, because this charging method can provide high efficiency and high stability charging experience for you.<br />OVER-VOLTAGE & OVER-CURRENT PROTECTION - 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. ">