The nested positioning support kit is a positioning aid tool that provides developmental support for hospitalized premature and sick infants in prone (abdominal), supine (back), or lateral (side) positions. There are two versions of it suitable for different environments: one is a reusable style made of washable baby knitted cotton, and the other is a disposable style made of soft non-woven fabric and flame-retardant polyester fibers. It is crucial that both versions do not contain DEHP and BPA, ensuring the safety of vulnerable newborns.