If a vacuum is forming in the S-bottle, this indicates that the silicone anti-colic valve at the bottom of the S-bottle is not working properly. Before each use, check that the air hole in the anti-colic valve is open by squeezing it.
If a vacuum is forming in the S-bottle, this indicates that the silicone anti-colic valve at the bottom of the S-bottle is not working properly. Before each use, check that the air hole in the anti-colic valve is open by squeezing it.