This sheet of IEC 60819-3 specifies requirements for four types of unfilled aramid papers: Type 1: Calendered paper. Type 2: Calendered paper, with improved tearing resistance and conformability. Type 3: Uncalendered paper. Type 4: Calendered paper, with lower density for laminating. Materials which conform to this specification meet established levels of performance. However, the selection of material by a user for a specific application should be based on the actual requirements necessary for adequate performance in that application and not based on this specification alone.