This is an original DIN 931 spec bolt with a 14 mm head. During most Porsche 356 production, 8 mm bolts and nuts were used with 14 mm across the flats of the head (= 14 mm wrench). Total length is 30 mm, under head to end of threads; threaded portion is 18 mm. These bolts are made in Germany and have a black oxide finish. Head marking is the German manufacturer "Graeka".

These bolts are used in various applications on 356 models such as:
• Transmission Intermediate Plate
• Steering Coupling