Per the information provided, the Warmer Mattress (SKU 67202) fits the neonatal intensive care unit warmer. It is composed of an outer mattress and an inner mattress. Both pieces are made from a polyurethane foam covered in CPU150 HF, a polyester knit fabric with a polyurethane coating. The inner mattress can be removed and replaced with a Womba Pod (see NYRL N319092) to transport a baby to another neonatal intensive care unit.
[1] Please importantly note that only the relevant portion of the related is displayed above. You may refer to the said customs ruling for the entire ruling explanation.
[1]. https://rulings.cbp.gov/ruling/N319096