HF660FHD HnF SKU Port (inch) A (inch) Hex (inch) HF640FHD-04-04 1/4 1.00 0.62 HF640FHD-06-06 3/8 1.25 0.81 HF640FHD-08-08 1/2 1.43 0.94 HF640FHD-10-10 5/8 1.69 1.06 SAE 010107