European standard chains are covered by DIN8187 and ISO606 standards. There are 3 versions:
Simplex
Duplex
Triplex
Pitch size varies between 4 mm to 114.3 mm, with the chain links having a large pin diameter. The chains therefore have better wear resistance due to the bearing area being of a greater size.
The ISO standard has a simple numbering system:
The first two digits are the pitch size and are measured in 1/16 s of an inch, for example 08 = 8/16
B indicates European Standard
The suffix indicates the number of strands in a chain