HLS-3.5 HEICO Fastening Systems HEICO-LOCK Washers , Manufacturer Part#: HLS-3.5 , Manufacturer: HEICO Fastening Systems , Brand: HEICO-LOCK Washers , UOM (Inch or Metric): Metric , Material: Steel , Finish: Zinc-Flake Coated , Bolt Size: #6 UNC (M3.5) , Inside Diameter: 0.150 Inch (3.90mm) , Outside Diameter: 0.300 Inch (7.60mm)