This foil material is still used exclusively for lidding in blister packaging today, usually in conjunction with a rigid plastic ‘blister’. However some formats now use foil on foil and this has the advantage of being less prone to damage, thanks to strong puncture resistance. Also the foil on foil combination can maintain the product, which is often highly sensitive to moisture or light ingress, over extended periods – increasingly important in biomedicines where they are being used or stored in difficult environments. Medical devices, from the simple syringe to highly sophisticated dosing mechanisms are also contained in flexible bags or foil packs to protect them and enable a sterile or moisture free environment to be maintained.