All Stainless Steel strand, cable and wire rope is manufactured to Federal Specs RR-W-410E.  Test certificates are available.   Domestic in origin.  Non-Domestic stainless steel cable also available on request. 
Breaking strength load limits and working load limits are different.  The working load limit is less and generally considered for safety working load usage in applications.  Example, a 500 lbs breaking strength may only have a safe working load limit of 100 lbs.  This safety factor depends on the manufacturer.  Safe working load limits based on manufacturer are available upon request.  For Rigging Purposes uses the manufactures Safe Working Load Limits not the Breaking Strength.

Much of the world uses the metric system - except for the United States and a few other countries.  Moving towards the metric measurement system has been slow, yet will be increasingly necessary to convert English units into SI - International System of Units - or metrics.
In measuring rope diameter, the industry has leaned toward a "Soft" conversion to metric during this long transition period.
For example, a 1" inch diameter wire rope would convert to 25.4mm in metrics.  Using the soft conversion, this is changed to the whole metric size that most nearly parallels the 1" inch size range or 26mm.
In sizes smaller than 5/8", the wire rope diameter is rounded to the nearest 0.5mm.  Most inch sized cables are produced in 1/8" increments, so a true and exact match may not be possible.
The following table gives the closest equivalent metric diameters for rope sizes up through 5 inches.  You will notice that the metric sizes are based on the "Soft" conversion.  Any cable or wire rope quotes will be subject to the "Soft" conversion sizes.
For Carbon Steel Metric Rotation Resistant cable sizes refer to this chart.