Had normal, smooth teats of NUK and a free Genius sucker. The normal vacuum cleaner, our Spatz always quickly lost or spit, because they were so smooth. The Genius sucker he loves and keeps them in there too. I think the really great shape, because they adapt to the palate. The silicone teats are especially super strong and durable, easy to clean and will not be dull. Thumbs up!