HLS-39 HEICO Fastening Systems HEICO-LOCK Washers , Manufacturer Part#: HLS-39 , Manufacturer: HEICO Fastening Systems , Brand: HEICO-LOCK Washers , UOM (Inch or Metric): Metric , Material: Steel , Finish: Zinc-Flake Coated , Bolt Size: 1-1/2 Inch UNC (M39) , Inside Diameter: 1.590 Inch (40.40mm) , Outside Diameter: 2.300 Inch (58.50mm)