Pigeon N/Peristal Nipples "L"-Fast Flow, Super-Stretchable; Teat Section Has An “Accordion-Like” Portion That Enables It To Stretch In Response To The Peristaltic Movement Of The Baby’s Tongue. Ultra-Soft Silicone; The Nipple’s Surface Is Very Soft, Yet It Does Not Collapse Easily. Made From Thick Ultra-Soft Silicone Material, The Nipple Has Similar Elasticity To That Of A Mother’s Actual Breast. The Dome-Like Shape Makes Baby’s Mouth Open Naturally, Supports Its Mouth Softly And Fits Its Lips Gently.