Made From Thick Ultra-Soft Silicone Material, The Nipple Has Comparable Elasticity To That Of A Mother’S Actual Breast. The Dome-Like Shape Makes Baby’S Mouth Open Naturally, Cares Its Mouth Softly And Fits Its Lips Softly. Pigeon S-Type Nipple Is Super-Stretchable With Slow Flow. Teat Section Has An 'Accordion-Like' Portion That Enables It To Stretch In Response To The Peristaltic Movement Of The Baby'S Tongue.