Double end bolts :

  DIN 938
ENGINEER STUD / Studbolt. Inserted end = 1 x d
 DIN 939
ENGINEER STUD / Studbolt. Inserted end = 1.25 x d		 DIN 940
ENGINEER STUD / Studbolt. Inserted end = 2.5 x d		 PN-68/H-74302
Studbolt