A removable protective cap?
The cap will protect your drink and the mouthpiece from impurities during transport, even on the muddiest routes.Feel free to remove it if you don't need it to make the bottle easier to use.
How to care for your water bottle
Clean the water bottle well after each use. If you use isotonic drinks, rinse well all body, cap and teat components to make sure there are no liquid residues. In order to properly clean the bottom of the water bottle, use washing-up liquid and a long brush.
Then leave to dry completely and store without the cap to allow the water bottle to air out properly.
Otherwise, mould may appear inside the water bottle.
Avoid using the dishwasher (especially >70°C).