Shimano Di2 Shifter Replacement

Hey everybody,
Unfortunately I wiped out today and snapped off one the Di2 shifters on my road bike. I’m trying to figure out which one I need to buy in order to replace it. Can anybody here tell me of there’s a part or model number inscribed anywhere on these shifters so that I can reliably order the correct part? Just looking for some help in identifying the part that I have. If it helps at all, this is the standard groupset that came on the 2015 Cervelo S3.
Thanks in advance!!

You probably have the Ultegra 6870 shifters, like these below. This is mostly a guess based on the vintage of your bike and the model.

https://media.chainreactioncycles.com/is/image/ChainReactionCycles/prod136572_Grey_NE_01?wid=586&hei=498

Thanks!

Roll back the rubber hood and you will see the part number is molded into the shifter body.