USB3.1 (also called Gen.2) brings many improvements to the previous standard USB3.0 (Gen.1). The most noticeable is the new Type-C connector which is much smaller than the previous standard connectors, it is also reversible.
USB3.1 Type-A to Type-C
Reversible connector (Type-C)
Data Transfer Rate: 10Gbps
Charging Output: 3A
Type A to Type C
This cable features both a Type-A connector and a Type-C connector making it the perfect solution for connecting modern mobile devices with a Type-C connector to a PC that doesn't have a Type-C connector yet.
USB Power Delivery v2.0
The USB3C-921 supports up to 20V / 3A (60W) of power. The new improved power delivery allows you to charge not only small mobiles devices such as mobile phones and tablets, but also laptops.
The new USB Type-C connector is smaller than most of the previous USB connectors. (Micro B is the exception.) It is also symmetrical; this allows you to plug the connector in either way up.