The Pro-Series 18.8 sets are high-strength studs made in Germany.
A special steel is used which has a tensile strength of 1850 N/mm² after tempering.
All threads are formed and not cut as commercially available. The so-called "rolling" of threads increases the strength of the tooth flanks by approximately 30%.
All Pro-Series products are supplied with a nickel coating and are therefore protected against long-term corrosion even under the toughest conditions.
A big advantage of Pro-Series over other manufacturers are the nuts and washers included in the set as these also have a tensile strength of 1850 N/mm².
