Aerotight M8 A2 Grade Stainless Steel Self-Locking Nut Thread Size (Nom) - M8 Pitch - 1.25 mm A/F Max- 13.0 mm N-Dia Max - 12.53 mm H Max - 10.0 mm F Min - 6.12 mm Aerotight self locking nuts are: All metal Stiff nut with no inserts Can be re-used Will stay in position whether tightened down or not No special tools required When assembled on the screw, 2 full threads should protrude through the nut A2 stainless steel has good resistance to corrosion except in severe industrial and Marine Condition. Use A4 in a marine environment.