They have a hex flange head and 60-degree deep single thread. They have been surface hardened with anti-corrosion Zinc Yellow coating for increased durability. SpectreÔäó Coach Screw. AB 36-38 & 55-56, BT (all), FK 17-21, HS (all), IM (all), IV (all), KA 27-28, KW (all), PA 20-99, PH 15-99, ZE (all), Channel Islands.
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