This is a USB-C male to USB-A female adaptor I bought on eBay. It's also known as a USB-C OTG adaptor. It can be used with phones and laptops.
In my case, I bought if for use with my Macbook Pro and my Nexus 5X. It's better suited to a phone with a case, since the little protruding white collar around the USB-C connector greatly reduces the contact surface area when used with a laptop. As a result, the mechanical connection is very flimsy and the connector could break very easily.
However, I didn't get to actually test the adaptor. I bought two from the same seller, and unfortunately neither worked. It's very hard to test the continuity of each pin with a multimeter, since the pins are so small. So instead, I ripped one of these useless things apart.
The construction of the adaptor looks fairly solid, or at least it would be if it actually worked. The pins are all moulded in plastic, which is quite hard to pull off.
But I can't recommend buying these things unless you're really poor. I bought some higher-quality cable-type adaptors which work much better.
USB-C pinout: http://pinoutguide.com/Slots/usb-type-c_pinout.shtml
Andrew Lorimer, November 2017