The SDNselect 3-in-1 SD card reader is a convenience device that enables you to read and write SD card data with your PC, Mac and Smart Phone. With the USB-C and MicroUSB connector (using finger nail to pop from the standard USB connector) and OTG capability, you can access data on an external SD card using your smart phone (does not support iPhone/iPad) when you do not have a computer around. It reads/writes to both SD and MicroSD card formats. The aluminum body will ensure it does not get damaged easily when you are on the field.