Micro-USB Chargers were widely used to charge smartphones. Now there are three types of chargers that charge smart phones. As the popularity of the USB charger is fading it's still used in many of the older phones. The Micro USB has a wide end. The USB-C has a smaller end and is becoming popular for the newest smart phones. So if you're looking to purchase chargers it's best to get a variety so you will have what your customers are looking for.