HLB-6 HEICO Fastening Systems HEICO-LOCK Washers , Manufacturer Part#: HLB-6 , Manufacturer: HEICO Fastening Systems , Brand: HEICO-LOCK Washers , UOM (Inch or Metric): Metric , Material: Steel , Finish: Zinc-Flake Coated , Bolt Size: M6 , Inside Diameter: 6.50mm , Outside Diameter: 13.50mm