PERLOK Insulation Plates are designed to secure insulation, coverboards and base sheets to approved substrates. The plate’s circular design and reinforcing ribs provide exceptional strength and resist wind uplift forces. PERLOK 3” Metal Insulation Plates are approved for use with PERLOK #12DP, #14HD, #14SSHD, #15EHD, Fluted Concrete Nail and ¼” Concrete spike fasteners.