Datatool System 3

[phillvr6]

I've got a Datatool System 3 on the new bike, I'm probably being a spanner but I can't work out where the batteries go in the transmitter, I've taken the rubber cover off but can't see any batteries.

Thanks,

Phill

[phillvr6]

Any idea what sort of batteries they are?

[phillvr6]

Thanks