 Reprocessors are licensed to issue a Packaging Recovery Note (PRN), or PERNs for exported packaging, for each tonne of specific material they have recovered.Regulated companies must buy the appropriate quantity of PRNs for the appropriate materials as proof they have fulfilled their obligations.For a percentage of each tonne of packaging waste generated, a PRN is required as proof that a tonne of that material (wood, paper, glass, plastic, aluminium or steel) has been recycled.