Most SON hubs (apart from SL connection type) use spade connectors.
The connection at the hubs terminals require a two 4.8 x 0.8 mm Female spade connectors, each connecting to the positive and negative poles on the hub.

Coaxial Connector:
Coaxial connectors are sold by SON as a way to allow for more convenient way to connect/ disconnect cables from the hub- as well as further up the wiring loom. The coaxial system is ideal for users who are looking for a durable connector, but being easier and quicker to use than the standard spade connectors.

SL Connector:
 these are only made by SON and are effectively a connection free system- as rather than having caps or spades plug into a terminal on the hub- the hubs axle contacts a connection plate integrated into the fork dropout. These are fairly rare, and only custom frame builders use the SON SL system for the highest level of integration.