Works perfect with my Spectra S2! There are not a lot of options as far as extra bottles & accessories for the Spectra pump, so I was excited to find these. The quality is amazing and I love how easy the adaptors are to use and the containers are thick and durable so easy to use & to clean/sterilize. Thought 10 might be too many, but it’s been the perfect amount! Would recommend this to any plumping mama, especially if you hen the Spectra pump.