On this page, you can find all monitors with a USB-C connector suitable for the MacBook 12 inches. Unlike all other MacBook models, every 12-inch MacBook (2015 to 2017) uses USB-C (3.1 gen 1). It looks the same as a Thunderbolt 3 connector, but it certainly isn't. A USB-C port isn't compatible with a Thunderbolt 3 device. Choose a monitor with a USB-C port for your MacBook 12 inches. Expect a speed of up to 625 MB/s (5 Gbit/s).