Example and table with designation. Type a: with entirely or partially hexagonal body. Material: alloy steel (class 3, according to UNI 5700-65); hardness class 2 and test torque class a, according to UNI 6396-68.
UNI 6748-1970 history
1970UNI 6748-1970 Hand operated tools. Double ended socket wrenches, 90 degrees offset one end, heavy series.