DIN 65542 Aerospace; countersunk head screws, close tolerance, with ribbed TORQ-SET (ACR) recess and MJ thread, short thread length, nickel alloy, nominal tensile strength 1250 MPa, for temperatures up to 315 °C/425 °C

standard by Deutsches Institut Fur Normung E.V. (German National Standard), 03/01/1987