Over the past year I've answered more questions about these strings than I can count. Hopefully, this will clear some things up.
There once were made some strings called Velvet Compàs 180 strings. These were the arco counterpart of the Compàs 360 strings. This formulation of the Velvet Compàs was made up until around 2002, and many of these still are around being sold.
It got confusing when Velvet stopped production on the Compàs 180 strings to make a more arco friendly version. They re-released the strings under the same name, despite the fact that they are completely different strings.
THE NEW Velvet Compàs 180 strings:
From Lou Roten
There are four formulations of compàs 180®: (The last design tweaking of
the 180's I'm told)
- standard tuned set (27 kg, red top) for orchestral playing.
Newly introduced
- standard/solo set (24 kg, black top) can be tuned in standard pitch and
solo (this is the SUIT set)
The SUIT was the formulation introduced about a year or so ago to be used
in both tunings.
- solo set for solo tuning only
- fifths tuning ('Red Mitchell' tuning)
To confuse matters further, a rumor has gone around the Velvet Compàs 180 SUIT strings are the old formulation. This is not true, although the old formulation was a standard/ solo tuning set.
HOW TO KNOW IF YOU HAVE THE OLD SET:
The old set can be easily determined by gold loop ends at the tailpiece. They also were copper/ aluminum wound (a little rough), and could leave oxidization on your hands. All of the new sets are attached in a completely different way, and are just straight string on both ends, and need to be tied on the tailpiece end.
Hope this clears some things up.
Monte