Cap not included.

Here is the answer:
"The transparent cap that your New Active Top bottle was placed over the mouthpiece / bite valve on the acquisition, is not a protective cap in the traditional sense, but a pure transport packaging.
Our NEW ACTIVE TOP has been designed intentionally without protective cap for bite valve, there for reasons of hygiene is better not to put on a cover over the bite valve. Such a cover / cap dirt would be the ideal breeding ground for the formation of bacteria.
This we wanted to be absolutely avoided. "

Too bad you have to hope that the mouthpiece is not too dirty before drinking so.