HF664FHD HnF SKU Port (inch) A (inch) Hex (inch) HF664FHD-04-02 1/4-1/8 0.91 0.62 HF664FHD-04-04 1/4 1.01 0.62 HF664FHD-06-04 3/8-1/4 1.28 0.81 HF664FHD-08-06 1/2-3/8 1.36 0.94 HF664FHD-08-08 1/2 1.46 0.94 SAE 010106