Available in many sizes. Compatible with Spectra wide-neck bottles Soft silicon material safe for babies BPA free and latex free Sizes S (0-3 months) M (3-5 months) L (5-7 months) XL (7 months or above) Recommended for babies 0+ months. *You may receive teat design in either one of the 1st and 2nd product image (1.semi-transparent design, 2.clear design). Both teat designs fit the Spectra bottle perfectly and functions identically.