... 4. OEM 5. 32 pages per book Preschool Read Book This set of audio books including: National Studies, English, Pinyin, Cognitive, Literacy ... of the child. We have prepared a lot of sound books, for example , Mathematic , English learning, Classic Fairy Tales , Chinese learning ... the builtin standerd sound, it is very useful for children to learn language.specification(P1,P2,P3,P4):1. OID Head, use ...