Sealcon NP-13-BR high quality nickel plated brass locking nuts are liquid tight to 150 psi. PG 13 / 13.5 Thread. Sold Individually. Also known as Hummel # 1.161.1300.01. Sealcon PG 13 / 13.5 Nickel Plated Brass Locking Nuts provide a NEMA 4x & 6 (IP 68 & 69K), 150 PSIG (10 bar) Liquid Tight Rating.