Many are made with materials that will not absorb allergens, they may be filled with special foam to ensure that they remain hypoallergenic. (babycomfortauthority.com)
All meals being shipped to this greatly expanded area are packaged in special foam lined cardboard boxes and shipped with dry ice to keep them safe and fresh during transit. (fb101.com)
There are special foam wedges available in baby shops for this purpose. (newkidscenter.com)