HF41IF HnF SKU Size (inch) A (inch) Hex (inch) Thread HF41IF-02 1/8 0.52 0.31 5/16-18 HF41IF-03 3/16 0.56 .037 3/8-24 HF41IF-04 1/4 0.56 0.43 7/16-24 HF41IF-05 5/16 0.62 0.50 1/2-20 HF41IF-06 3/8 0.66 0.62 5/8-18 HF41IF-08 1/2 0.74 0.75 3/4-18 SAE 040110