One of the main complaints of the Apple iPad Pro is how slowly it charges with the standard Apple 12W USB Power Adapter. The Apple 12W USB Power Adapter provides 12 Watts (5.2 Volts @2.4 Amps) to your iPad Pro through a USB to Lightning cable and takes well over 3 hours to fully charge.
However, using the Apple 29W USB-C Power Adapter, the Apple iPad Pro leverages USB Power Delivery technology to charge at 29 Watts (14.5 Volts @2 Amps) to reduce total charging time by less than half. All you need is Apple's new Apple USB-C to Lightning Cable to connect the 29W USB-C Power Adapter to the iPad Pro.
Note the smaller Apple iPad Pro 9.7 does not support this fast charge capability through USB Power Delivery.