On an Alu Alu or CFF (Cold Formed Foil) blister pack both the base and lidding are made from aluminium-based film: OPA-ALU-PVC (nylon-ALU-PVC), making it possible to almost entirely eliminate water vapour permeability as well as oxygen and light ingress. These blister packs are made via a cold forming technique in which the laminate is pressed into a mould without applying heat, using forming pins to create the product cavity. The pack is then sealed with an aluminium lidding material.