This is the standard type of wrench-applied hexagon head, characterized by clean, sharp corners trimmed to close tolerances. Recommended for most general applications Stock sizes are M6 to M12 Thread Type (Metric Din 931). Some M16, M20 and M24 also available Bolts have some unthreaded shank (according to end length) Limited range of Imperial sizes can … Continue reading Nylon (Hexagonal Head) Bolts