OKOOKO soft baby books enlight baby's world. ・0-3 Months: Newborn baby's vision is blurred, the high contrast black and white patterns help stimulate baby's initial visual development. ・3-6 Months: Baby will be gradually sensitive to red color than black and white in this period. The black and white outlines are added with colors to keep baby's attention. ・6-12 Months: Colorful cartoon patterns improve baby's color sensitivity. High-definition pictures and cute drawings help baby recognize common animals and patterns. Black & White High contrast patterns help stimulate newborn baby's visual development. Colorful Various colorful patterns keep baby's attention when baby's vision is well developed. Tear Resistance Sturdy stitching and premium fabric committed, soft and safe to your baby. Soft Mirror There is a soft mirror stitched on the black and white crib book, don't forget to tear the protective film to get clear reflection. Hanging Rope There are 8 ropes on each baby book to hang the baby book on cribs, stroller or car seat. Crinkle Paper There are 2 crinkle paper inside each baby book, rustling sound keeps baby's attention effectively. Bath Toy OKOOKO soft cloth books can also used as bath toy for baby's bath time, they are washable, non-toxic and they dry fast. OKOOKO tummy time crib baby book toys, suitable for babies from 0 month and above. Black and white high contrast patterns help baby stimulate the retina and optic nerve. ・1 black & white high contrast crib book + 1 colorful crib book ・Cognitive Ability ・Visual Training ・Cultivate Instantaneous Memory ・Parent-Kids Interaction