PORON foam is hypoallergenic, breathable and is not made from latex. PORON foam has been used to cushion medical devices such as cushioning splints, prosthetic padding or neck braces due to it being non irritating, breathable, not allegenic and anti bacterial. The foam used in the inserts and the adhesive tape that sticks them to insoles have been certified by a medical product testing lab as safe for skin contactSee more benefits of medical polyurethanes at: https://www.rogerscorp.com/elastomeric-material-solutions/poron-medical-polyurethaneslong term comfortOpen-cell and breathableMicrocellular structureResistant to microbial growth