Just like the previous DURA-ACE dual control levers, these have 'hidden' buttons on top of the shifter hoods. You can set these up any way you like and I wrote an article on just that: setting up the Di2 shifter hood buttons.
Wireless and wired
While these shift levers support the new wireless Di2 shifting, you can also choose to connect it using EW-SD300 wires. Doing so will improve battery life by approximately 50%.
12-speed disc brake shift levers have one SD300 port and one satellite shifter (SW-RS801-T / SW-RS801-S / SW-RS801-E) port.