Self-locking hexagon nut (locknut) with a nylon ring to prevent loosening due vibration etc. ISO 10511 supersedes DIN 985; spanner sizes 16, 18 and 21 are now designed for M10, M12 and M14 respectively. Thread diameter-M16 Pitch of thread-1.50 mm Thread type-Metric Wrench/Spanner size-24 mm Height-10.5 mm Total height-16 mm Material-Steel Surface treatment-Zinc-plated Quality-10.9 DIN standard-985 ISO standard-10511 Measurements type-Metric