This self-locking hex nut with a nylon insert features a built-in locking mechanism that helps prevent the nut from backing off due to vibration or mechanical stress. Made from electro-galvanized steel, it's well-suited for indoor use or applications with very mild environmental exposure. With a strength class of 6, it pairs with bolts and screws rated 6.8 or lower. The thread type is British Standard Fine (BSF). These nuts are non-standardized, so dimensions may vary slightly depending on availability. Whitworth threads (BSW/BSF) are no longer recommended for international use; for new builds, we advise going with metric (M/MF/MEF) or Unified threads (UNC/UNF) instead.