2 pack of Buttons nighttime doubler inserts. Buttons’ natural bamboo/cotton nighttime doublers have 5 absorbent layers of 70% bamboo & 30% organic cotton for extra absorbency. They work as a doubler when snapped underneath Buttons daytime inserts. Buttons diaper inserts snap right into their nappy covers to avoid shifting. Your Bamboo inserts may seem large at first but they will shrink after being washed Large inserts fit babies from 15-25 lbs (inserts are about 13" in length after washing/drying) suitable for the One Size and Super covers