Three new vinyl films from Teknor Apex (City of Industry, CA; 800/556-3864) withstand the hot and cold temperatures of therapy packs. The new films exhibit brittle points as low as –40°F and exhibit high consistency and flexibility. They range from 68 to 92 in Shore A durometer with a 15 second delay, 2000–3200 psi in tensile strength, and 275–375% in elongation. The calendering process provides a uniformity of thickness that surpasses the uniformity achieved by extrusion. All calendered films contain materials that are listed by FDA in the Code of Federal Regulations 21 CFR.