These nylon cap nuts feature a round head with internal metric thread and a blind hole. They protect threaded ends from rust, damage, and dirt while reducing injury risk from sharp screw ends. Compatible with standard machine screws such as cylindrical, round head, countersunk, and hex types. Suitable for dry, damp, and outdoor environments. Available in sizes M3, M4, M5, M6, M8, and M12. Color: Black. Standard: GB. Material: Nylon. Pack of 5 pieces.